The Parole Board of Canada says a former Halifax naval officer convicted of spying for Russia is eligible for conditional release in three years.

Jeffrey Paul Delisle was sentenced to 20 years in prison after pleading guilty to charges under security-of-information laws for passing top secret information to Russia over a five-year period..

But the judge presiding over his case ruled that when time already served is taken into account, Delisle's sentence is 18 years and five months.

The parole board said Delisle becomes eligible for unescorted temporary leaves in March 2016 and day parole in September 2018.

He is eligible for full parole a year later.

A decision on whether Delisle would be granted parole is made by the board after a review of his case or a hearing.