OTTAWA - A new Amnesty International report questions whether Canada really wants to get to the bottom of torture allegations involving Afghan detainees.

The human-rights organization said Monday it has concerns that the investigation by Canadian authorities into abuse claims last spring may not have been "competent'' or "impartial.''

The scathing assessment, part of 51-page report on NATO's overall handling of prisoners in Afghanistan, also accused the Canada of blurring the number of insurgents captured and handed over to local Afghan authorities.

Amnesty International "remains gravely concerned that detainees handed over by (NATO) to the Afghan authorities are currently at substantial risk of torture and other ill-treatment,'' said the report, released Monday in Europe and North America.

"Of the five countries with agreements regarding detainee transfer, only the second Canadian agreement specifies provisions for investigation into allegations of torture or other ill-treatment. However, (Amnesty International) fears that investigations by the Canadian government into allegations may not have been `competent' and `impartial'.''

Amnesty's Canadian-based expert on Afghanistan said the group's harsh judgment is based on the Conservative government's protracted legal battle to keep government documents on detainee transfers secret.

"We've had difficulty tracking down the nature of the investigations, so we're not sure how competent they were,'' David Kelleher said in an interview.

Other countries, such Britain, the Netherlands, Norway and Belgium, were also criticized, particularly over losing track of prisoners handed to Afghan authorities.

Last spring, when he was foreign affairs minister, Peter MacKay -- since moved to the defence portfolio -- acknowledged that Canadian officials had received six allegations of abuse involving Canadian-captured prisoners since signing a revised agreement with the Afghans. Those claims and other accounts published by the media were investigated by both Canadian and Afghan authorities.

Neither country has said whether they've found evidence to substantiate -- or disprove -- the allegations. In fact the federal government has gone to great lengths to keep information about detainees secret.

Access To Information Act requests involving anything to do with detainees have been stamped national security and denied, whereas heavily censored reports were released in the past.

Last summer, federal lawyers invoked a little-used national security provision in the Canada Evidence Act to prevent lawyers for Amnesty and the B.C. Civil Liberties Associations from seeing Defence and Foreign Affairs Department records related to Afghan prisoners. Both organizations are in Federal Court to stop transfers of prisoners to the Afghans.

In the spring, there were claims that as many as three dozen prisoners handed over to local authorities by Canadian troops might have been tortured, even though Ottawa had signed a memorandum guaranteeing their safety.

The revelations prompted the Conservative government to sign an improved transfer agreement with the government of Afghanistan in May -- one that allows for Canadians to check on prisoners they capture.

But the Amnesty report says that is not a safeguard against potential torture because the monitoring happens after the fact.

"Monitoring detects the transgressions, but does not forestall them,'' the document said. "As such, monitoring cannot meet Canada's absolute legal obligation to prevent torture, although it can be helpful to inform Canada should Afghanistan breach its obligations to prevent torture and other ill-treatment.''

Foreign Affairs Minister Maxime Bernier was not available to comment, but his department issued a series of bullet points late Monday, defending the revised transfer agreement signed last May.

"Since signing this supplementary arrangement there have been real improvements in the monitoring and tracking of detainees,'' said the e-mail note from a department staffer.

"The arrangement makes explicit Afghanistan's obligations under international human rights law, and includes a provision that Canada, UN bodies and the Afghanistan Independent Human Rights Commission have full, unrestricted access to any person Canada has transferred.''

The department did not address Amnesty's specific concerns about the lack of accountability in the investigation of abuse claims.

Amnesty called on Canada and other NATO countries in Afghanistan to suspend the transfers of all detainees to Afghan authorities, particularly the country's notorious intelligence service.

It argues that the military alliance should hold on to prisoners until international monitors can be placed in Afghan jails to provide preventative monitoring of prisoners and to mentor local guards on humane practices.

Kelleher said the biggest concerns relate to detainees handed over to the country's notorious intelligence service -- the National Directorate of Security -- which reports only to President Hamid Karzai. The agency, with 30,000 employees across the war-torn country, operates with impunity and under laws unchanged since the Soviet occupation of the 1980s.