Medical marijuana growers hoping the federal government would be lax in implementing its new ban on self-grown pot next month are likely to be disappointed.

In a statement released Friday, Health Canada says that users who grow their own supply in their homes, or buy from small growers licenced under the old program, will not only have to destroy the stash before April 1, but also submit a form promising they've destroyed it and are no longer producing. Otherwise, Health Canada "will notify law enforcement."

This threat of legal action contradicts information in a Health Canada memo from last fall, in which the agency said it doesn't intend to share previous growers' personal info with law enforcement, Vancouver's Georgia Straight reports.

Users have to send in the form by April 30.

The changes to the medical marijuana program will limit legal growing to licensed companies which will mail out pre-dried packages of pot to those with a prescription. The federal government has certified 10 producers so far.

The government claims the new rules will reduce illegal trafficking and health hazards caused by growing the plant in private homes, but many users say they worry market prices will make the drug too expensive for them to buy. Health Canada estimates the average price of a gram will rise to $7.60 from the current price of $1.80 to $5, but one licensed company has already said it will offer a discount to those on social assistance or disability.

The federal agency also offers a suggestion on its website for destroying leftover marijuana, to add water to it before mixing it in with cat litter and throwing it out, a solution one user calls "ridiculous."

Opponents of the changes have threatened they might defy the new rules and a few are taking legal action. A B.C. lawyer has launched a constitutional challenge against the law, and an Ottawa couple has sued the federal government for $6.5 million.

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