OTTAWA -- A federal government agency made a financial contribution to a think tank with ties to the Trudeau government, to sponsor a conference that featured Liberal cabinet ministers as speakers.

The Social Sciences and Humanities Research Council paid a $15,000 sponsorship fee to Canada 2020, a self-described 鈥減rogressive鈥 think tank run by Tom Pitfield, a longtime friend of Prime Minister Justin Trudeau.

The opposition says the payment raises questions about the use of federal funds to support an organization already known to have close links to the prime minister and his party.

鈥淲hy are taxpayers鈥 dollars going to fund an organization that seems to be promoting, in all its work, the Liberal Party of Canada,鈥 asked Conservative MP Blaine Calkins.

The $15,000 payment was part of an agreement between SSHRC, which funds social science research, and where federal Infrastructure Minister Amarjeet Sohi gave the keynote speech.

According to a program for the conference, Natural Resources Minister Jim Carr was billed as a moderator at one of the sessions on innovation in the resources economy, and Bardish Chagger, then the minister of small business and tourism, also spoke.

The conference was held at the Chateau Laurier Hotel in Ottawa last November.

In a written statement, SSHRC said it funded the conference because one of its goals is 鈥渁ddressing Canada鈥檚 long-term, societal challenges such as innovation, including skills and talent development, which was the theme of this public conference.鈥

Pitfield has known Trudeau since both were young children. He is married to Anna Gainey, president of the Liberal Party of Canada.

Over the Christmas holidays, Pitfield and Gainey vacationed with Trudeau and his family at the private Bahamian island owned by the Aga Khan, a trip currently under review by the federal ethics commissioner.

Numerous Liberal cabinet ministers have appeared at past Canada 2020 conferences over the first year of the Trudeau government, including a forum on open government in April that featured Treasury Board President Scott Brison and Public Services and Procurement Minister Judy Foote as speakers.

Brison鈥檚 department denied it was funding the event directly but had paid $22,000 under a related contract to develop concepts related to open government.

At the time, Canada 2020 maintained that it has received financial support from previous governments and in the past has featured speakers from other political parties, including former Conservative cabinet ministers John Baird and Jason Kenney.

Last March, the organization sponsored an exclusive, star-studded party for the prime minister in Washington, DC, the night before Trudeau鈥檚 state dinner at the White House.

The government鈥檚 response to an opposition question about the event, tabled in Parliament this week, shows that Canada 2020 paid the travel costs of RCMP members who attended the event as a ceremonial guard.