*411OPINION OF THE COURT
Ross, J.We are called upon to determine whether these 36 plaintiffs, all Housing Authority Police Officers of the New York City Housing Authority, are required to vacate their present out-of-State residences and relocate within approved geographical areas of this State. Underlying this analysis is the elusive question of whether the defendant, a subdivision of the municipal corporation may be equitably estopped from enforcing this mandate. Under the circumstances presented herein, and in the interests of justice, the governmental unit should be estopped.
The operative facts are not in dispute. The plaintiffs, averaging more than 14 years of service on the Housing Authority’s police force, were appointed during the years 1953-1973. At the time of their individual appointments, each was a resident of New York State. The mandatory examination taken prior to appointment left unspecified a residence requirement. However, civil service examinations given at the same time for other peace officer positions specified residence in certain areas within New York State. Additionally, in a combined examination for Housing Authority Patrolman, New York City Transit Authority Patrolman and Correction Officer, given on November 22, 1969, a specified in-State residence was required for the latter two titles but not the first. Promotional examinations were to the same effect. Thereafter each purchased a home in the neighboring States of New Jersey and Connecticut and have lived in these locales for an average of seven years. Parenthetically, several plaintiffs have resided out of State for over 15 years. Most, if not all, moved only after receiving assurances from superior officers that their then contemplated move was lawful.
Prior to moving, these officers were aided by defendant in securing mortgages on their property. After their moves, defendant rendered further aid by securing New York State driver’s licenses and domiciliary pistol permits for plaintiffs.
On December 7, 1978, the Housing Authority Police Chief issued Memorandum No. 58, requiring all plaintiffs pursuant to section 30 of the Public Officers Law, to be residents of New York State and to reside within certain designated counties. The plaintiffs had until December 15, 1979, to comply therewith or face dismissal.
Plaintiffs then commenced these proceedings which are *412amply elucidated in the dissenting opinion. As noted by my dissenting brothers, Special Term correctly found, and I agree, that Housing Authority Police Officers are public officers within the meaning of the statute (Matter of Maye v Lindsay, 69 Misc 2d 276, revd 41 AD2d 127, reinstated on opn of Special Term 33 NY2d 552). However, as to these plaintiffs, the residency requirement should not be enforced.
Traditionally, courts and other adjudicatory tribunals have determined that equitable estoppel is not applicable to the government or its subdivisions. No doubt this rule found its genesis in that larger body of law of sovereign immunity (2 Davis, Administrative Law Treatise, § 17.01 et seq.). However, in recent times the judiciary has retreated from this rigid standard and currently employs a flexible medium in examining the specific facts of each case.
One court which has played a leading role in the liberalizing of the doctrine of equitable estoppel suggests that courts balance the harm suffered by a party who has relied on governmental action against the damage to the public interest (United States v Lazy FC Ranch, 481 F2d 985). This same court will only apply, and rightly so, equitable estoppel against the government if certain conditions are initially satisfied: "[t]he party to be estopped must know the facts * * * he must intend that his conduct shall be acted on * * * the [other party] must be ignorant of the true facts; and * * * he must rely on the former’s conduct to his injury” (United States v Georgia-Pacific Co., 421 F2d 92, 96).
While I am not prepared to categorically sanction the "balancing of interests” test, it can safely be said that equitable estoppel is applicable to all units of local government in exceptional cases to promote the ends of justice, where judicial intervention will far outweigh the manifest injustice that has occurred or will occur (Eden v Board of Trustees of State Univ. of N. Y., 49 AD2d 277; see, also, 2 Antieau, Municipal Corporation Law, § 16A.00 et seq.).
Any analysis of the problem presented herein must commence with a surmounting of the above-mentioned threshold criteria. Stated in an alternate fashion: "where a governmental subdivision acts or comports itself wrongfully or negligently, inducing reliance by a party who is entitled to rely and who changes his position to his detriment or prejudice, that subdivision should be estopped from asserting a right or *413defense which it otherwise could have raised.” (Bender v New York City Health & Hosps. Corp., 38 NY2d 662, 668.)
Applying the above, it is evident that defendant Housing Authority knew the residential status of their employees, and the law applicable to them. The open publication of examinations for entry level and promotional positions without a residence requirement, coupled with the affirmative aid given by defendant prior and subsequent to the out-of-State relocations rendered foreseeable plaintiffs’ reliance thereon. The dissent seems to argue that these plaintiffs are deemed to know the law. However, where there has been an authoritative interpretation of the law by a duly authorized officer, as here by the Director of Personnel of the City of New York; a mistake of law should estop the government. (21 U of Chi L Rev 680, 691.) Moreover, it has also been argued that, where the government fails to speak when there is a duty, the government will be estopped (79 Col L Rev 551, 559). Clearly, the duty to enlighten was ever present as to these plaintiffs. I believe the dissents’ reliance on Matter of Gavigan v McCoy (37 NY2d 548, 552) and Matter of Albert Simon, Inc. v Myerson (36 NY2d 300, 303) is misguided. In Simon, the opinion does not suggest that there was reasonable reliance upon the governmental agency finding that pinball games are not gaming devices. In Gavigan, it was not claimed that the petitioner reasonably relied upon his out-of-title assignment as lawful.
It is important to note defendants acknowledge that they do not subscribe to "the simplistic and obsolescent doctrine that estoppel may never lie against public agencies.”
Defendants argue that for over. 20 years the Housing Police have been seeking equality with other police forces of the City of New York. To this end the General Counsel of the Housing Authority issued an opinion dated April 22, 1977, reasoning that Housing Authority Police Officers were public officers required to live within New York State. Yet subsequent thereto, three promotional examinations conducted on August 31, September 24, 1977, and March 30, 1978, failed to specify a residence requirement when such was clarified less than one year before.
Equitable estoppel is a vital doctrine now more actively invoked than in years past. Courts throughout this State have applied this doctrine under any number of circumstances. (See for example Bender v New York City Health & Hosps. Corp., *414supra; the doctrine applies to notice of claim; Eden v Board of Trustees of State Univ. of N. Y., 49 AD2d 277, supra; the State has been estopped from asserting claimed lack of capacity to contract with petitioners; Matter of Moritz v Board of Educ., 60 AD2d 161; the board of education has been estopped from denying that teacher is tenured; Matter of 1555 Boston Rd. Corp. v Finance Administrator of City of N. Y., 61 AD2d 187; the City was estopped in area of taxation where manifest injustice is present; also, see, 21 NY Jur, Estoppel § 76.)
"It is the principle of estoppel that brings flexibility and justice to the law of municipal corporations” (2 Antieau, Municipal Corporation Law, § 16A.00). Presently the imposition of equitable estoppel will not work a serious injustice nor unduly damage public policy. Its application to these 36 plaintiffs is limited and will prevent a "manifest injustice”.
I can conceive of no more important function of our courts, than shielding our citizens from an overbearing (or as here, a negligent) governmental agency.
Accordingly, the order, Supreme Court, New York County (Asch, J.), entered on July 3, 1979, granting plaintiffs’ application for a preliminary injunction, and denying the plaintiffs’ cross motion for summary judgment as premature, should be modified, on the law, to the extent of declaring that Police Officers of the Housing Authority of the City of New York are public officers within the meaning of section 30 of the Public Officers Law and subject to the residency requirements therein, but defendants are equitably estopped from imposing these requirements on plaintiffs, and, as so modified, the order should be affirmed, without costs.