The lawyer for a Canadian naval officer who confessed to selling military secrets to the Russians says he might raise the issue of security lapses at his sentencing in January.

Mike Taylor says he was stunned Sub-Lieutenant Jeffrey Paul Delisle wasn't caught sooner by officials who failed for years to pick up on his illicit behaviour.

He finds it baffling that Delisle used such crude methods as floppy discs and thumb drives to smuggle sensitive data from his secure office in Halifax.

Taylor believes the way the 41-year-old was paid by the Russians should also have been picked up by Delisle's superiors at HMCS Trinity.

Delisle pleaded guilty earlier this month to breach of trust and espionage.

He was arrested in January after a trip last fall to Brazil, where he met his Russian handler to discuss his future with the agency.