The Aga Khan could face an investigation into allegations he violated Canada's Lobbying Act by giving Prime Minister Justin Trudeau and his family free vacations on his private island in the Bahamas at the same time as he was discussing funding for projects.

Democracy Watch sent a letter to the Commissioner of Lobbying late Wednesday, urging her to investigate whether Prince Shah Karim Al Hussaini Aga Khan IV "violated the Lobbyists Code by giving Prime Minister Trudeau and Liberal MP Seamus O'Regan the gifts of trips to his island home."

In the letter, Democracy Watch co-founder Duff Conacher says the Aga Khan's actions have put Trudeau and O'Regan in a conflict of interest. It is also against the law to give a public office holder a gift that could create a sense of obligation.

"Your position must be that anyone working for or associated with a company that is registered to lobby a public office holder who gives to or does anything for that office holder… that is more than an average voter does… puts that office holder in an apparent conflict of interest," he wrote.

The Aga Khan is the spiritual leader of millions of Ismaili Muslims and is listed as a member of the board of directors of the Aga Khan Foundation Canada. The foundation, which has received millions of dollars in federal government development aid over the years, is registered to lobby several federal government departments including the Prime Minister's Office, although the Aga Khan is not listed among those registered to lobby on its behalf.

Trudeau Vacation 20170110

Trudeau meets with the Aga Khan on Parliament Hill in Ottawa on May 17, 2016. Dawson ruled Wednesday that the PM should have recused himself from part of the meeting. (Sean Kilpatrick/Canadian Press)

A search of the lobbyist registry shows the foundation has filed 132 reports since 2011 outlining its meetings with government decision makers. However, none of those reports list any meetings with Trudeau.

Representatives of the Aga Khan Foundation of Canada contacted by CBC News have yet to comment.

The call for a lobbying investigation comes in the wake of a scathing report by Ethics Commissioner Mary Dawson on Wednesday.

Dawson found that Trudeau violated four sections of the Conflict of Interest Act when he accepted a vacation on the island in the Bahamas and a ride in the Aga Khan's personal helicopter.

While Trudeau and his family got a tropical vacation, Canadian taxpayers got a bill for more than $215,000 in transportation and staffing costs — far more than the government initially disclosed to Parliament.

Bell Island Terrace

A terrace on the Aga Khan's property overlooks the turquoise-blue waters of the Bahamas. (CBC)

Dawson also revealed that Trudeau's trip during last year's Christmas holidays was one of three that Trudeau or members of his family had made to the island. Dawson disclosed that Sophie Grégoire-Trudeau stayed on the island in March 2016 with a friend and their children.

Neither the Aga Khan, nor any member of his family, was on the island during their stay.

Dawson said the Aga Khan was on the island during the Trudeaus' Christmas-time visit last year as was a "senior American official of a previous administration," who she did not name.

In her report, Dawson describes the relationship between Trudeau and the Aga Khan, the times they met and the questions they discussed.

Among them was a bilateral meeting on May 17, 2016 that was arranged by "representatives" of the Aga Khan. After a 15-minute chat between the two men about "personal matters, the Ismaili community in general and geopolitics," they were joined by three of the Aga Khan's representatives, Heritage Minister Mélanie Joly, staff members from the Prime Minister's Office and senior officials of the Privy Council Office.

Bell Island lookout

A wooden pathway leads to a scenic lookout on Bell Island in the Bahamas. (CBC)

Dawson's report says the government had found a funding mechanism to allow it to contribute to the Global Centre for Pluralism's endowment fund and Trudeau reaffirmed the government's $15 million commitment during the meeting.

The Aga Khan's pitch for government funding for a $200 million riverfront renewal plan in Ottawa was also discussed.

Dawson ruled that Trudeau should have recused himself from two discussions in May 2016 involving the $15 million grant.

"Two months prior to the May 2016 occasions, Mr. Trudeau's family accepted a gift from the Aga Khan that might reasonably be seen to have been given to influence Mr. Trudeau in the exercise of an official power, duty or function as Prime Minister," she wrote.

Bell Island at night

Looking out from Bell Island in the Bahamas at night. (CBC)

"For this reason, the discussions with the Privy Council Office and later with the Aga Khan about the outstanding $15 million grant to the endowment fund provided an opportunity to improperly further the private interests of the Global Centre for Pluralism."

While the Aga Khan is not paid to lobby government (one of the criteria under the law) Conacher said he believes the Aga Khan violated the lobbying rules. Otherwise, it would create a giant loophole, he said.

"Every single corporation, business, union, non-profit organization would start using board members to give gifts to politicians if this loophole were opened up by the lobbying commissioner."

Conacher is also calling for outgoing lobbying commissioner Karen Shepherd and incoming lobbying commissioner Nancy Bélanger to recuse themselves from ruling on the investigation because of the way Shepherd's contract was renewed and the way Bélanger was chosen in "a secretive, PMO-controlled process."

Manon Dion, spokeswoman for the lobbying commissioner's office, said she cannot reveal whether they are already looking into the issue.

Elizabeth Thompson can be reached at elizabeth.thompson@cbc.ca