Prime Minister Stephen Harper downplayed concerns Thursday over an arrest warrant for Arthur Porter, the former head of the committee that oversees Canada's spy agency.

While Harper was minimizing worries about Porter's top secret security clearance and privy councillor status, Public Safety Minister Vic Toews attacked the opposition parties for not challenging the government on the appointment when they had the chance in 2008.

On Wednesday, Quebec's anti-corruption unit issued arrest warrants for Porter and others involved in building a new hospital in Montreal. Porter is also the former head of the McGill University Health Centre in Montreal. He was appointed chief executive in 2004.

The now-embattled Porter was appointed by Harper to the Security Intelligence Review Committee (SIRC) on Sept. 3, 2008, then appointed as head of the committee on June 23, 2010. Because of the work they do, board members are sworn in as members of the Privy Council and have access to top secret information.

The Conservatives have insisted that allegations against Porter have nothing to do with the work he did with SIRC.

"You know, I don't know what to say. This is obviously a matter that's ultimately going to be before the courts. I just point out that none of these matters relate to his work in his former federal responsibilities," Harper said Thursday in Rivière-du-loup, Que.

Porter stepped down from the job after the National Post reported his ties to controversial international consultant Ari Ben-Menashe in 2011 and said Porter tried to solicit $120 million in Russian government financing for Sierra Leone, the country where he was born. The money was to go through a Porter family company.

At the time, Dr. Porter was also claiming to be Ambassador Plenipotentiary for Sierra Leone, an apparent conflict of interest with his appointment at SIRC.

Appointment by PM 'inexplicable'

New Democrat Leader Tom Mulcair said it's inexplicable, given Porter's background, how he ended up as "the head of what is essentially Canada's CIA."

"I mean, how did he wind up in that job? We are looking at certain connections between him and some other people that were close to the Conservatives, but for that we're going to wait a little while," Mulcair said.

According to an old biography of Porter's on the SIRC website, the committee's duties include examining "reports by ministers relating to the national security of Canada."

In question period, interim Liberal Leader Bob Rae asked why Toews suggested yesterday that it was up to the opposition parties to vet government appointments.

"The opposition parties, Mr. Speaker, do not have the capacity to do a security clearance. They do not have a capacity to investigate, they do not have a capacity to cross-examine, they do not have the capacity to do the work which is supposed to be the work of the government," Rae said.

"Where are the security clearances for this government?"

Prime Minister Stephen Harper downplayed concerns Thursday over an arrest warrant for Arthur Porter, the former head of the committee that oversees Canada's spy agency. (Ryan Remiorz/Canadian Press)

Toews put the blame for Porter's appointment on the NDP and Liberals, arguing the parties didn't contest the appointment. Toews is the minister responsible for CSIS and SIRC.

"Now the member stands up and says I didn't have any information so I simply consented. That is an abdication of his responsibility. If there were any concerns that he had, he could have brought it to the attention of the appropriate authorities and simply asked the question. He failed in his responsibilities," Toews said.

Rae was not the leader of the Liberal Party at the time of Porter's appointment.

Yesterday, Rae, a former member of SIRC, said it's a ridiculous argument to make. The government, he said, gives the opposition party leaders three or four days to contest an appointment.

"And with the situation of Mr. Porter, it's the government that had a monopoly on all the facts," he said.

"If you're a member of the committee on our security agencies, you have access to a lot of information that's top-secret information, that you can't reveal to whoever, whenever, so it's important to know exactly how Mr. Porter's name arrived on Mr. Harper's desk, and that's the question. I think he has to answer that question."

Arrest warrant includes fraud charge

Porter, who now lives in Nassau, Bahamas, is facing charges of fraud, conspiracy to commit fraud, fraud towards the government, breach of trust, participating in secret commissions and laundering proceeds of crime.

The construction project links Porter to former SNC-Lavalin executives Pierre Duhaime and Riadh Ben Aïssa, who are subject to arrest warrants for the same investigation but also face scrutiny in separate instances.

Duhaime was arrested in November 2012 and appeared in court on Feb. 11 accused of fraud, conspiracy to commit fraud and for producing false documents. The charges announced Wednesday are not related to the ones laid in 2012.

He was removed from his duties at SNC-Lavalin in March 2012 after an independent investigation suggested he had approved money transfers worth $56 million to two unidentified people.

Ben Aïssa, on the other hand, is being detained in Switzerland in connection with suspected corruption, fraud and money laundering in connection to projects in North Africa.

According to RCMP documents, Ben Aïssa allegedly bribed the son of now-deceased dictator Moammar Gadhafi with $160 million for a contract in Libya.

A spokeswoman for SNC Lavalin said Wednesday that the company is unequivocal "that no unethical behaviour or illegal acts must ever be tolerated.

"We believe anyone found to have committed any wrongdoing in connection should be brought to justice," Lilly Nguyen said.

Too ill to travel

In a statement yesterday, Porter said he was surprised and angered to find out about the arrest warrant from the media.

"Whilst I am certain there is no basis in fact, I have yet to see any documentation," Porter said.

"Since I left Montreal in 2011, I have been subjected to scurrilous and scandalous allegations in the media. However, I have never been contacted by the Montreal, Quebec or Canadian authorities in regard to this or any other matter. When I am provided with official information, it will be reviewed and appropriate action will be taken."

Porter runs a cancer treatment centre in Nassau. In January, he told CBC News that he diagnosed himself with inoperable lung cancer.

On Thursday, he told the Associated Press that he has late, stage-four cancer and is too ill to travel from the Bahamas to Canada.

Porter said during an interview in his home that if Canadian investigators want to question him they should fly to the Bahamas.

Porter says the cancer has spread to his liver.

with files from the Associated Press