Canada’s ethics commissioner is looking into allegations that Justin Trudeau breached the Conflict of Interest Act when he accepted an offer to travel on the helicopter of a billionaire friend whose foundation does business with the government.

Pressed by reporters in Kingston, Ont., Prime Minister Trudeau admitted Thursday that he accepted an offer from the Aga Khan to have him transported from Nassau, Bahamas to the remote Bell Island during his recent vacation, adding “We don’t see an issue on that.”

Trudeau also told reporters that he is happy to answer any questions that conflict of interest and ethics commissioner Mary Dawson “may have."

Dawson’s office confirmed she has “commenced a preliminary review.”

Under the Conflict of Interest Act, ministers of the Crown are not allowed to “accept travel on non-commercial chartered or private aircraft for any purpose unless required in his or her capacity as a public office holder or in exceptional circumstances or with the prior approval of the (Conflict of Interest and Ethics) Commissioner.”

NDP Leader Tom Mulcair said Thursday that Trudeau had “broken the law” because the Conflict of Interest Act “clearly forbids the Prime Minister and his Ministers from taking trips on private aircraft for non-government purposes.”

“He claims that this was a family vacation and not government work,” Mulcair added. “These were not exceptional circumstances and therefore cannot excuse the use of a private helicopter. This is a clear conflict of interest and it’s worrisome that the prime minister has been so evasive about the specifics of this trip.”

The Conservative Party said on Twitter that the “Conflict of Interest Act is clear” and that Trudeau “admitted to breaking the rules.”

Conservative Leadership Candidate Andrew Scheer called on Dawson earlier this week to examine whether Trudeau’s stay on the Aga Khan’s island was a violation of the act.

The Trudeaus have already faced controversy for their vacation to Nassau, Bahamas because they flew in a taxpayer-funded government jet and initially refused to tell reporters where they had gone.

Trudeau has reimbursed the treasury $4,900 for flying his family and a nanny to the Bahamas.

Although it costs far more to use the government’s Challenger jet, it is standard practice for vacationing prime ministers to pay only the equivalent of what commercial flights would cost.

St. John’s-Mount Pearl MP Seamus O’Regan and Liberal Party President Anna Gainey were also on the trip.

The helicopter travel may break Trudeau’s own ethics guidelines. Those guidelines forbid the use of sponsored travel in private aircraft except for exceptional circumstances and only with the prior approval of the ethics commissioner.

The Aga Khan is the spiritual leader of the world's Ismaili Muslims. The Aga Khan Foundation of Canada receives tens of millions of dollars a year from Canada for development work.

In 2009, Parliament made the Aga Khan an “honourary Canadian,” with the Conservative MP who put forward the motion calling him “a beacon of humanitarianism, pluralism and tolerance in the world.”

With a report from CTV’s Omar Sachedina in Kingston, Ont. and files from The Canadian Press