The Foreign Affairs Department has adjusted upward the number of detainees who have alleged they were abused after being captured by Canadian forces in southern Afghanistan and transferred to Afghan jails.

There are now six abuse allegations, a spokesman for Foreign Affairs Minister Peter MacKay said late Friday.

Andre LeMay said the department has been keeping track of reports since Canada signed a new detainee monitoring agreement in May.

On Wednesday, MacKay and Public Safety Minister Stockwell Day told a joint parliamentary meeting that four allegations of abuse involving Taliban suspects had been reported.

Day said the four prisoners making the claims showed no visible signs of abuse. Taliban fighters have been coached to allege mistreatment while in detention, he added.

LeMay said the Afghan government will be working closely with the country's Independent Human Rights Commission to investigate the claims.

The latest revelation could boost a legal challenge by Amnesty International and the B.C. Civil Liberties Association, which have applied to Federal Court for an injunction to halt the transfers.

They argue that Canada could find itself complicit in torture if it knowingly hands prisoners over to authorities who will abuse them.

The first two claims, which surfaced in April, set off bitter opposition attacks against the Conservative government of Prime Minister Stephen Harper.

After two weeks of contradictory explanations, the Conservatives signed a revised transfer agreement with Afghanistan that allows Canadian officials direct, private access where the condition of detainees can be checked.

The initial agreement, inked by the former government under Paul Martin in the early weeks of the 2005-06 election, did not provide such access.

With files from the Canadian Press