Federal Health Minister Jane Philpott's use of a luxury car service owned by a Liberal Party supporter will be probed by parliamentary ethics commissioner Mary Dawson to see if the minister violated the Conflict of Interest Act.

Last week Philpott was revealed to have spent $3,700 over two separate days for a high-end car service in the Toronto, Hamilton and Niagara areas and another $3,815 for 20 trips to Toronto Pearson International Airport.

On Aug. 18, Conservative health critic Colin Carrie wrote a letter to Dawson asking for her office to investigate Philpott's use of Executive Sedan Livery Service, owned by Reza Shirani, who campaigned for the minister in the last federal election.

In Dawson's reply to Carrie, she said that her office will now investigate whether Philpott violated section 7 of the Conflict of Interest Act which reads:

"No public office holder shall, in the exercise of an official power, duty or function, give preferential treatment to any person or organization based on the identity of the person or organization that represents the first-mentioned person or organization."

After Philpott's car expenses were made public, the minister issued a statement saying that she has instructed her office to review her expenses, that any inappropriate expenses would be reimbursed and that she would take steps to ensure that she did not err again.

MPs Francis Scarpaleggia, Gerard Deltell and Alexandre Boulerice discuss the rules around ministers' expenses. 7:20

On Monday, the plot thickened for the minister when The Canadian Press, supplied with a receipt by the Conservative Party, reported that Philpott also charged taxpayers $520 for an annual membership to Air Canada's executive lounge network in North America and Europe.

Philpott said she would pick up the tab for that perk as well.

Philpott addressed the Canadian Medical Association's annual convention in Vancouver Tuesday afternoon. Afterwards she was asked why her office only decided to act on her expenses after they were revealed in a series of media reports.

She said that she takes full responsibility and that her office does not have the right systems in place but was taking steps to ensure it did not happen again.

"Some of this, as you may, know is a matter that is being brought up by the ethics commissioner, and so I will defer my discussions about that matter with her," she said.

Trudeau on the defensive

After attending a Liberal cabinet retreat in Sudbury, Ont., ​Prime Minister Justin Trudeau was asked by reporters on Monday if he raised the issue of ministerial expenses with his cabinet.

Trudeau said that the Philpott incident was a mistake, and when such an occurrence happens, he expects his ministers to acknowledge it, apologize for it, make amends and make sure it does not happen again.

"This situation was a reminder for all of us to be extremely careful about our expenses and about the public trust that we wield," he said.

The prime minister was on the defensive again Tuesday during an infrastructure announcement in Toronto, when he was asked about Environment Minister Catherine McKenna's $6,600 bill for photography during her attendance at the COP21 climate summit in Paris last fall.

"We have seen over the course of the past months, have noticed many long-standing government policies that we are questioning and that's certainly one that we are looking at as perhaps not the best use of public funds," he said of the photography costs.

Details of the photography expenses were contained in documents obtained under the Access to Information Act and given to The Canadian Press by the Conservatives.