VANCOUVER -- Changes to the medical marijuana program that will force patients to stop growing their own pot will violate the rights of those who won't be able to afford marijuana under the new system or obtain strains that work for them, their lawyer told Federal Court on Tuesday.

More than a decade after a landmark court case forced Ottawa to legalize medical marijuana, a group of patients were in Federal Court on Tuesday asking a judge to temporarily block new regulations that will limit production to approved commercial growers.

As of April 1, patients currently licensed to grow or possess medical marijuana under the old system will be breaking the law unless they dismantle their grow-ops and destroy their plants and seeds.

The patients' lawyer, John Conroy, urged the judge to issue an injunction to allow those patients to continue growing and possessing marijuana under the old regulations until their legal challenge goes to trial.

He argued the law will deprive the patients of their right to access important medicine, and he pointed to the federal government's own research that concludes medical marijuana prices are expected to initially increase when the new rules take effect.

"The legislation not only doesn't address the poor or those who can't afford (marijuana under the new system), but it takes away the right to produce completely," Conroy told the court.

"The government ... has come up with a scheme that doesn't create a supply to everyone and expects those who can't afford it to wait and see what happens over time instead of preserving the constitutional rights of the patients."

Dozens of people filled the public gallery, including patients and medical marijuana advocates, some of whom could be seen smoking pot outside before the hearing started. The distinct smell of marijuana hung in the courtroom as lawyers presented their arguments.

The federal government first introduced its medical marijuana regulations in 2001, a year after an Ontario court found the law violated the rights of sick people who used pot to alleviate their ailments.

The number of people authorized to possess -- and often grow -- marijuana has increased to 37,000 this year from fewer than 100 in 2001.

The Conservative government announced a significant overhaul of the system last year and has since been accepting applications from commercial growers.

The federal government has defended the new regulations by arguing home grow-ops pose numerous hazards, including mould, fire, toxic chemicals and the threat of home invasion by criminals.

Conroy told the court the federal government has presented little evidence to show medical marijuana growers represent a significant risk to the public.

He said the government is instead relying on anecdotes from police. Even then, Conroy said the government has identified only a few hundred problem cases out of tens of thousands of medical marijuana licences.

"We don't dispute for a minute that there is abuse," said Conroy. "We just say that the abuses and the abusers shouldn't be allowed to prejudice the legitimate users."

Jan Brongers, a lawyer for the federal government, said there is no constitutional right to subsidized medicine. He rejected the patients' claims that medical marijuana will be out of reach under the new regime.

"The evidence doesn't show it will be so expensive that these plaintiffs, who apparently can afford to set up and maintain their own operations, will be completely unable to afford this legal supply of marijuana," said Brongers.

He said the government's goal of protecting the public should outweigh the patients' concerns about price and quality.

Brongers also argued that allowing the new system to take effect will help the court to see how patients are actually affected by the time the case makes it to trial.

"We submit that if the motion (for an injunction) is dismissed, it would give the new commercial marijuana market a chance to get off the ground," said Brongers.

"It will ensure that when this court actually conducts a trial, it can do so with the benefit of evidence of months worth of practical experience."

Health Canada has said anyone licensed to grow under the current rules must sign a form by April 30 confirming they have stopped growing and have destroyed their plants. The department has warned that anyone who doesn't comply will be reported to police.

The patients' lawyer also asked for an injunction that would prevent Health Canada from following through on that threat.

The judge said he expects to rule on the injunction application by Friday.

A trial date has not been set. Brongers said a trial would likely be scheduled for early next year, though the judge suggested the case may be heard earlier than that.