A group that was to host George Galloway says a decision to bar the controversial British MP from entering Canada is an affront to free speech and smacks of political interference by the Conservative government.

James Clark of the Toronto Coalition to Stop the War says Galloway's ban is a politically driven decision aimed at preventing the airing of views with which the government and Immigration Minister Jason Kenney disagree.

British MP George Galloway has been denied entry into Canada. (CBC)

Canada's Border Services Agency labelled Galloway a threat to national security for his controversial views on the war in Afghanistan and support of the Palestinian group Hamas, which is listed as a terrorist organization by the federal government.

Earlier this month, Galloway made a highly publicized trip to the Gaza Strip to deliver humanitarian aid.

"The vast majority of the aid delivered by Mr. Galloway was administered by the Red Crescent," Clark said. "Canada is the only country in the world choosing to interpret that as a terrorist act."

Galloway's Ottawa lawyer, Jamie Liew, says her client is not a terrorist and finds barring his entry concerning.

"The government's position is stretching the definition of terrorist," Liew said. "And we find it a disturbing precedent."

Kenney confirmed last week that he would not overrule the decision to ban Galloway, who was scheduled to speak in several Canadian cities after his current U.S. tour.

"It is very strange that a country like the U.S., with similar laws and values to ours, has allowed Mr Galloway to move freely, but we have not," Bloc Québécois MP Serge Ménard said.

"If there's one thing Quebecers and Canadians share it's that freedom of speech is a core value," he said.

Lawyers working on behalf of Galloway are challenging the ruling on a number of fronts, Liew said.

In addition to filing an application for judicial review of the decision in federal court, the group has also submitted a motion asking for a temporary injunction against the move, because such rulings can often take a lot of time.

Galloway is scheduled to speak March 30 at a Toronto conference called Resisting War from Gaza to Kandahar, hosted by the Toronto Coalition to Stop the War.

New Democrat MP Olivia Chow was also on hand, and agreed that the government's decision smacks of politically-motivated censorship.

"He is banned from coming to Canada because he delivered clothing to orphaned children in Gaza," Chow said. "The Harper Conservatives are afraid of anyone who speaks out for peace."

With files from the Canadian Press