Conservatives and New Democrats hammered Liberal Leader Justin Trudeau in the House of Commons Monday for collecting speaking engagement fees from charity groups, despite Trudeau saying he would refund any organization that feels it didn’t get its money's worth.

Between 2006 and 2009, Trudeau earned $1.3 million for public speaking engagements. He revealed the details of his personal income during his campaign for the Liberal leadership earlier this year. At the time, Trudeau said he stopped accepting paid public speaking engagements after he launched his leadership campaign.

The Conservatives, who have been struggling with the Senate expense scandal for weeks, have seized onto Trudeau’s paid speeches.

Heritage Minister James Moore said Trudeau should have never accepted any money from any charities -- before or after becoming an elected official.

"Members of Parliament showing up at a charity event should give money to charities, not take it away," Moore said during question period.

Trudeau responded by pointing to the ongoing Senate investigation involving the prime minister’s former chief of staff Nigel Wright and Sen. Mike Duffy.

"Will the government choose transparency over secrecy? Will it publicly release a copy of the $90,000 cheque written by the prime minister’s (former) chief of staff to Mike Duffy?"

Moore fired back, saying the Liberal leader needed to "come clean" about his own controversy before lecturing others on accountability.

"What is it about the ethical standard of giving money to charities rather than taking money from charities that he doesn’t understand?" he asked.

Moore's remarks come after Trudeau said on CTV's Question Period on Sunday that he is willing to "make it right" with any charitable organization that has paid him in the past and is consequently unsatisfied with the results.

"I’m willing to pay all the money back, if that’s what it comes to," Trudeau said during the interview. He was addressing an issue first raised in reports about his work with The Grace Foundation, which funds a long-term care seniors’ home.

According to the New Brunswick charity, they paid Trudeau $20,000 to speak at an event last year that aimed to fundraise $300,000 but ended up losing money instead.

It is the only organization so far that has stepped forward to ask for a refund. But NDP Leader Thomas Mulcair believes Trudeau should return all the fees he's collected from charity groups since he was elected in 2008 -- not just from those asking for their money back.

"I think it's a mistake for a sitting member of Parliament to be accepting money from a charity to do what is essentially part of your job, which is to talk to Canadians about your priorities and how you see things unfold," Mulcair said.

On Monday, the Conservatives circulated documents showing that Trudeau was the speaker at three charity events for the University of Guelph, Georgian College in Barrie, Ont. and a business dinner event hosted by the Ontario municipality of Chatham Kent. According to the documents, all three events lost money.

During the Liberal leadership race, Trudeau voluntarily revealed he earned more than $1.3 million on public speaking engagements since 2006, including $277,000 from 17 groups after being elected as an MP in 2008.

Trudeau repeated Monday he plans on contacting each of those groups to see if they want their money back.

"I will be happy to pay them back personally if they are dissatisfied," he said. "I will talk with them about anything that they want to do. I am open. What I am demonstrating here is a level of openness and transparency, accountability that has never been seen before on this Parliament."

Saskatchewan Premier Brad Wall says Trudeau’s decision to refund any money to charities that have paid him to speak and felt dissatisfied is the "right thing to do."

Late last week, Wall called on Trudeau to refund the $20,000 speaking fee he collected to a Saskatoon literacy conference. The organization was left with a surplus of just $7,000.