The opposition parties' calls for International Co-operation Minister Bev Oda to resign got louder Wednesday over her admitted role in doctoring a document that cut off funding to a faith-based foreign aid agency.

During question period Wednesday, NDP Leader Jack Layton accused Oda of being "unworthy of being a minister," and accused Prime Minister Stephen Harper of "condoning the forging of documents," and "misleading the House of Commons."

Layton said: "She forged a document and used the bureaucracy to cover it up. She is unworthy of being a minister." He went on to ask when the funding to KAIROS, the faith-based agency, would be restored.

Harper continued to defend his minister, saying that she had fulfilled her duty as a minister by ensuring Canadian taxpayers' money was properly spent, and that the final decision on the funding was hers as the head of the Canadian International Development Agency (CIDA).

"(Her) decision was contrary to a recommendation that she received from unelected officials, but in a democracy it is elected officials who decide how to spend taxpayers' money," Harper said.

At a press conference earlier Wednesday Liberal Leader Michael Ignatieff vowed his party will continue calling for Oda's resignation, saying her presence in Parliament is an affront to "the integrity of the democratic system."

Oda has faced tough questions and criticism since she acknowledged on Monday she had a role in changing the document.

She had previously told a Commons committee she didn't know how the document approving the funding had come to have the word "not" added in, effectively cancelling the funds.

Oda's admission prompted opposition MPs to call for her to be found in contempt of Parliament.

"This is about democracy. You cannot have a democracy if a minister of the Crown fails to tell the truth to the people elected by the people to get at the truth. That's why she has to go," Ignatieff said.

"This is not about her personally, this is not about Mr. Harper, it's about the integrity of the democratic system. Of course she has to go."

The House of Commons foreign affairs committee has voted in support of a motion rebuking Oda, and was expected to submit a report to House Speaker Peter Milliken, but a decision on the recommendations is not expected for several weeks. Parliamentary scholar Ned Franks said Wednesday the contempt of Parliament accusations may have merit.

"Falsification of documents, as far as I know, is a criminal offence and that document was falsified," Franks, a professor emeritus at Queen's University, told CTV News.

So far, Harper has stuck by Oda, dismissing calls for her to resign or be fired.

However, he has not directly addressed the issue of Oda doctoring a document signed by CIDA officials.

The document that was altered was a statement recommending millions of dollars in funding for KAIROS, a faith-based overseas development group.

Oda and two CIDA officials had signed it. However, "not" was later scrawled on the document.

Nipa Banerjee, a former CIDA employee who now teaches at the University of Ottawa, said agency employees only send memos to the minister when they are recommending that funding for a project be approved.

Banerjee told CTV's Power Play Wednesday that in her 30 years at the agency, it was never standard practice to alter a document.

"Normally what (the minister) does is to write down that ‘I do not approve this project,' but she would not alter the memo," Banerjee said.

On Wednesday, Ignatieff accused Harper of ordering Oda to change her position to reflect the PMO's stance, saying "That came straight from the Prime Minister's Office."

"They put the 'not' in on orders from the Prime Minister's Office and then she's sent out to a parliamentary committee to basically tell untruths to the Canadian people and their representatives," Ignatieff said.

"I just think this is really simple, this woman, this minister, has to go."

When asked what proof he had that the order had come directly from the PMO, Ignatieff said only that "nothing happens in this building without the explicit, expressed authorization of the prime minister."