Vancouver marijuana activist Marc Emery is serving a five-year-prison sentence in the U.S. Sam Leung/Canadian Press

Jailed Canadian marijuana advocate Marc Emery has been denied a transfer to Canada from a U.S. federal prison where he's serving a five-year sentence for selling marijuana seeds to Americans through the mail.

Emery, of Vancouver, the self-described Prince of Pot, was extradited to the U.S. last year where he pleaded guilty and began serving his sentence, but he was eligible to apply for a transfer to a Canadian prison to serve out his term.

Emery was told his request for a transfer was rejected on the basis of the seriousness of the offence and because of U.S. law enforcement concerns, his wife, Jodie Emery, said Friday.

She said she's shocked because she had expected he'd be allowed to serve his jail time in Canada.

Emery is currently in a federal jail in Oklahoma City, awaiting transfer to a medium-security prison in Mississippi.

He can apply for a transfer to Canada again in two years.

During Emery's sentencing in Seattle last September, a U.S. lawyer said he made millions of dollars shipping seeds into that country, putting his personal profits above the law.