A Canadian flag with a marijuana leaf is flown during a 4/20 rally to demand the legalization of marijuana on Parliament Hill in Ottawa, April 20, 2012. Reuters/Patrick Doyle

Canada will press the US to alter a border policy that has barred Canadians who admit to having used marijuana from traveling to the US, given that Canada plans to legalize pot, a government spokesman told Reuters on Friday.

The case of a Canadian man barred from US travel because he admitted to having smoked pot recreationally has stirred debate over US border agents invoking a federal law against marijuana use, even though pot use is legal in several states and soon to be legal in Canada.

British Columbia resident Matthew Harvey was stopped at a US border crossing in Washington state in 2014 and asked about recreational marijuana use.

When Harvey, 37 at the time and who had a permit to use medical marijuana, said he had smoked pot recreationally, he was detained and questioned for six hours before being denied entry and barred from future entry.

"They said that I was inadmissible because I admitted to smoking marijuana after the age of 18 and before I'd received my medical marijuana licence," Harvey said, according to the CBC.

In an interview with the CBC, Canadian Public Safety Minister Ralph Goodale said that the situation needed to be addressed, particularly in light of uneven marijuana restrictions in US states.

Canada's Public Safety Minister Ralph Goodale speaks during Question Period in the House of Commons on Parliament Hill in Ottawa, Canada, February 24, 2016. REUTERS/Chris Wattie

"We obviously need to intensify our discussions with our border authorities in the United States, including the Department of Homeland Security," Goodale said on Thursday.

"This does seem to be a ludicrous situation," he went on, noting that marijuana was legal in Washington state as well as "three or four other jurisdictions in the United States."

"[T]here's certain ironies about the current American position that we will certainly be very vociferous in putting before them," Goodale added.

Four US states — Washington, Colorado, Alaska, and Oregon — have legalized recreational marijuana use, as has the District of Colombia. Moreover, 25 states have legalized medical marijuana, at least five of which will decide on recreational-marijuana legalization in November elections.

While a spokesman said on Friday the Canadian government has been speaking to the US government to ensure officials are aware of Canada's plans to legalize marijuana, the controversy over Canadians being stopped at the border and barred from future travel to the US has not been addressed.

A man smokes marijuana during an annual 4/20 rally on Parliament Hill in Ottawa, Canada, April 20, 2016. REUTERS/Chris Wattie

"In terms of the practices of border guards in question, those only came to widespread attention recently and will be discussed in future bilateral discussions," said Scott Bardsley, spokesman for Goodale, according to Reuters.

Goodale has said his countrymen should be "well advised to understand" that the US could enforce whatever laws it saw fit.

He has also referenced some of the shortcomings in the two countries' marijuana policies.

"The present marijuana regime that has existed now for many years in both Canada and the United States has clearly failed Canadian and American young people because North American teenagers are among the biggest users of marijuana in the western world," Goodale said.

In the US, the Controlled Substances Act lists marijuana as a Schedule I drug, meaning it officially has not accepted use. The US DEA has balked at rescheduling it several times in recent years, though a senior policy adviser to Hillary Clinton said the Democratic presidential candidate would reschedule the drug should she win the office.

While Harvey, the Canadian man stopped at the border and denied future entry to the US, can apply for a travel waiver to be admitted temporarily, it is expensive. It currently costs $585 and will go up to $930 later this year, according to the CBC.

Moreover, waiver issuance is discretionary, meaning the agent issuing it can decide the amount of time for which it is valid. Once it expires, the applicant will have to pay and go through the process again.

Current Liberal Prime Minister Justin Trudeau campaigned on a promise to legalize recreational marijuana, and the government has said it would introduce legislation by the spring of 2017.

(Reporting for Reuters by Andrea Hopkins; Editing by David Gregorio)