The nominee for federal ethics watchdog won't commit to completing ongoing investigations into the prime minister or finance minister if he gets the job.

But Mario Dion tells the House of Commons ethics committee that if he is appointed, reviewing the files would be a top priority so he could understand them fully before deciding if and how they should proceed.

Outgoing conflict of interest and ethics commissioner Mary Dawson is currently looking into a trip Justin Trudeau took to the Aga Khan's private island last Christmas, as well as the finance minister's role in tabling new pension legislation that could impact his family's company.

But with Dawson's term at an end, there's no guarantee those reviews will be completed before she leaves — and no requirement for her successor to do so.

Both the NDP and the Tories have expressed frustration with how the search for Dawson's replacement was handled, saying they were never consulted by the government.

Dion told the committee he decided to apply for the job in August and was interviewed in mid-November for about an hour before being named to the post this week.