OPINION
MATTHEWS, Justice.Thomas Nelson entered a plea of guilty to a charge of burglary not in a dwelling. The charges concerned a drinking bout by Nelson and two friends which culminated in a break in at a pharmacy. Some drugs and petty cash were taken; the trio was apprehended on the scene at about 10:30 o’clock at night after a “prowler” call to the Kodiak Police Department.
Nelson was initially sentenced, to serve five years in prison, which is the maximum for the charge. The sentence was suspended and he was placed on probation for five years. Probation was to expire on November 2, 1981.
As part of the conditions of probation, he was admitted to an alcoholism program as an inpatient on November 2, 1976. On December 23, 1976, he was released to outpatient status, which lasted two more months. In July, 1977, he pled guilty to an OMVI charge; in August, he was accused of breaking and entering a residence, but evidently no charges were filed.
About this time, Nelson and his wife were obtaining counselling at a local mental health clinic, and he appeared to be making progress there. A petition to revoke probation based on his drinking and the alleged unauthorized entry was filed, but before a hearing was held Nelson left town. Apparently, after leaving Kodiak, Nelson went to Washington state, then took a job in a cannery at Sand Point, Alaska. Eventually, Nelson turned himself in to the authorities in February, 1978; in April, he admitted to three counts of the petition to revoke probation.1
Pending reimposition of sentence, Nelson was placed in an Anchorage rehabilitative facility. On May 9, 1978, after a month there, he went AWOL, got drunk, and was arrested for malicious destruction by local police.
On May 12, 1978, a probation revocation hearing was held in Kodiak. The court at the hearing expressed concern that the initial five-year sentence might have been overly severe. The court therefore ordered Nelson imprisoned for three years and denied eligibility for parole. This appeal followed.
When Nelson was originally sentenced to serve five years in prison for the crime of burglary not in a dwelling the court did not mention parole eligibility. Nelson, by operation of law, would have been eligible for parole after serving one-third of the five year period of confinement. AS 33.15.080; AS 33.15.230. Execution of Nelson’s sentence was suspended pursuant to AS 12.55.-080 and Nelson was placed on probation. Another statute, AS 33.05.070(b), provided that if Nelson’s probation were revoked he could be required to serve the sentence imposed, “or any lesser sentence. . . .”2 Nel*504son’s probation was revoked and, while he was given a shorter term to serve, three years, his eligibility for parole date was extended from 1.67 years under the original sentence to three years under the revocation order.
An increase in the minimum period of incarceration required before becoming eligible for parole is an increase in the sentence. Shagloak v. State, 582 P.2d 1034, 1036-38 (Alaska 1978); Faulkner v. State, 445 P.2d 815, 819 (Alaska 1968). When Nelson was originally sentenced he was in jeopardy in the constitutional sense. Thereafter, the prohibition of the fifth amendment of the United States Constitution against double jeopardy prevented any amendment to his sentence which had the effect of increasing it. Shagloak v. State, 582 P.2d 1034, 1037 (Alaska 1978); Faulkner v. State, 445 P.2d 815, 820 (Alaska 1968). The revocation order increased the minimum period that Nelson must spend in jail from 1.67 years to 3 years and to that extent violated his double jeopardy rights. Moreover, the increase also violated the command of AS 33.05.070(b) that the court upon revocation of probation may order the defendant to serve the sentence originally imposed, or a lesser sentence, but not a greater one.
The case is remanded for imposition of all or a portion of the sentence originally imposed and suspended.3
. After his return from Sand Point, the petition to revoke probation was amended to include two counts based on the unauthorized departure and failure to check in with his probation officer. Nelson admitted these violations and the drinking, but did not admit committing the crime.
. AS 33.05.070(b) provides:
(b) As speedily as possible after arrest the probationer shall be taken before the court for the district having jurisdiction over him. Thereupon the court may revoke the probation and require him to serve the sentence imposed, or any lesser sentence, and, if imposition of sentence was suspended, may impose any sentence which might originally have been imposed.
.We express no opinion on whether the initial five-year sentence was excessive, nor as to whether reimposition of the entire amount at this time would be proper. The trial court may find it useful, in determining an appropriate disposition on remand, to refer to the ABA Standards Relating to Probation, § 5.1 (Approved Draft 1970), particularly to the references provided in the Commentary at 51-58. See generally Gilligan v. State, 560 P.2d 17 (Alaska 1977); Martin v. State, 517 P.2d 1399, 1403 (Alaska 1974).