Prime Minister Justin Trudeau is firing back at the Conservatives after days of questions over ministerial fundraising events open only to those who spend hundreds of dollars to get in the door.

Speaking to reporters at a press conference to mark the Liberals' first year in office, Trudeau took direct aim at the Official Opposition. Both the Conservatives and NDP have questioned the Liberal fundraisers.

"The Conservative Party had a very different approach to fundraising than this government does," Trudeau said.

"They chose to name people like Mike Duffy or Irving Gerstein to the Senate and charge them with the responsibility of raising money for the Conservative Party of Canada. We have a very different perspective on the Senate and a very different perspective on fundraising."

Duffy, a former broadcaster, was a star Conservative senator who frequently travelled to fundraising events across Canada. Gerstein, who was in charge of the Conservatives' fundraising arm, proudly proclaimed himself a party bagman.

Duffy has sat as an independent since the Senate spending scandal, in which he was accused of abusing expenses. He maintained his innocence and was cleared of all charges last spring.

Gerstein retired last February.

Finance Minister Bill Morneau has been at the centre of criticism that the Liberals are breaking ethical rules set out in Trudeau's mandate letters to his cabinet ministers. Last month, Morneau was the star attraction at a Halifax fundraiser where tickets cost $1,500, nearly the maximum annual donation. The money goes to the Liberal Party, which says the events are open to anyone with a ticket. The Globe and Mail reported the party has held 20 fundraisers featuring cabinet ministers.

Lobbying Commissioner Karen Shepherd says she's investigating whether the events place the ministers in a potential conflict of interest.

The concerns follow on a cash-for-access scandal with the Ontario Liberals, which led Premier Kathleen Wynne to introduce new rules. Trudeau said Wednesday the federal rules are already the strictest in Canada.

"The fact is there is total transparency. Anyone who gives significant amounts of money, under the legal limits of course, is fully disclosed to Canadians," Trudeau said.

The names of federal donors, the recipient and the amounts contributed are posted quarterly to the Elections Canada site, but the reason for the donation - for example, if it is for a ticket to a specific event with a particular politician - is not listed.

Last spring, CTV News reported Justice Minister Jody Wilson-Raybould appeared at a Toronto fundraising event at a law firm. Tickets cost $500 each and raised almost $9,577 from 20 donors once expenses were subtracted.

Ethics Commissioner Mary Dawson said Wilson-Raybould didn't break any rules, but that MPs should consider making them tougher.

This story has been changed to correct the cost of the ticket to the Halifax fundraiser with Finance Minister Bill Morneau.