A former New Democrat MP is calling on the conflict of interest commissioner to investigate Defence Minister Harjit Sajjan.

Craig Scott, who represented the Toronto-Danforth riding until October 2015, is challenging Mary Dawson to look into the minister's refusal to call an inquiry into the handling of suspected Taliban prisoners during the Afghan war.

While in opposition, the Liberals promised to conduct a full investigation into the former Conservative government's policy of allowing the army to hand over detainees to Afghan authorities, particularly the intelligence service in that country, which was accused of practising torture.

Scott called on the government to live up to its word last spring using an e-petition, an appeal Sajjan rejected.

Prior to running for office in 2015, the defence minister was a reserve force lieutenant-colonel who had done three tours of Afghanistan, acting as a liaison with local Kandahar authorities, an intelligence officer and finally as an adviser to the U.S. commander overseeing NATO's southern command in the war-torn country.

Sajjan should not have been the one deciding whether to hold an inquiry into the detainee controversy, Scott said in a letter to the conflict commissioner, obtained by CBC News.

"It is my sincere and considered belief that minister Sajjan is very likely in possession of information dating back to his time when he was in the Canadian Armed Forces that would almost certainly be of great relevance to any commission of inquiry," he wrote. "This places him in a conflict of interest because of his personal interest."

A spokeswoman for the commissioner acknowledged the complaint has been received, but no decision has been made on a full-fledged investigation.

Sajjan 'served honourably, bravely and effectively'

During his time in Kandahar, Sajjan had contact with many of the local officials — the governor and the head of the intelligence service — who have been accused of directing, and even participating in, the torture of suspected Taliban fighters.

Scott, who is also an international law professor, argued the minister has a vested interest in protecting the institution of the military, but also underlined that he is not accusing Sajjan of any involvement in the transfer of prisoners to possible torture.

Under international law, it is considered a war crime if one country hands over prisoners knowing that they will be abused.

The complaint about Sajjan is strictly limited to his refusal to call an inquiry, Scott said.

An Afghan suspect is interrogated during a joint Canadian-Afghan army patrol in the Panjwaii District of Kandahar province in 2009. (Colin Perkel/Canadian Press)

"Allow me to emphasize that none of what I have said or will say in this letter, and none of what I have said before or in future on this matter, is meant to cast any aspersions on minister Sajjan's service in the military," Scott said.

"On the contrary, I have every reason to believe he served honourably, bravely and effectively — and this may be an understatement. I also have no reason to believe minister Sajjan was part of the decision chain surrounding whether or not detainees would be transferred to the risk of torture."

At the very least, Scott argues Sajjan should have recused himself and allowed another minister to make the decision.

Minister denies conflict

The complaint is an attempt to make "political hay" where there is none, Sajjan said.

"I was not involved in any potential type of conflict here," he told CBC News. "Somebody is trying to turn this into a political situation."

Sajjan also downplayed his role in Afghanistan, suggesting it has been exaggerated.

"There is a lot of myth and folklore around my position," he said. "I was always a reservist. People talk about the great intelligence work I did, but keep in mind I was never an intelligence officer. I was brought in for my policing experience and my understanding of cultural aspects."

His job was to build a rapport with ordinary Afghans, but he acknowledged he established contact with a number of key local officials, such as the notorious former governor Assadullah Khalid and Ahmed Wali Karzai, the half-brother of the former president, both of whom were accused of human rights abuses.

The nub of Scott's complaint is that Sajjan must have some kind of information about what was going on — something the minister denies, saying his group operated in "a bubble" and decisions about the detainee policy were made at a higher level.

He was asked whether the subject of the treatment of prisoners ever came up in conversation with Afghan officials.

I was trained to a very high ethical standard," said Sajjan. "If I had anything, I would have been obligated to report it at that time. - Defence Minister Harjit Sajjan

"I was trained to a very high ethical standard," said Sajjan. "If I had anything, I would have been obligated to report it at that time. And my reporting of the current situation, at that time, was done."

He did not elaborate on what he reported. A spokeswoman later clarified that Sajjan's battlefield reports to his superiors are classified but suggested they would not have contained references "about the transfer of detainees, torture or human rights abuses."

Sajjan said Canadian troops served with "absolute credibility and honour" and abided by the Geneva Conventions on the treatment of prisoners.

The issue of whether the former Conservative government knew — or ought to have known — about the possibility of torture in Afghan jails was the subject of a military police complaints commission inquiry and multiple court cases.

It also shook former prime minister Stephen Harper's government to the core in 2009 when the Liberals — in opposition at the time — threatened to defeat the minority Conservatives.

It was that principled stand Scott chose to focus on with his e-petition.