OTTAWA -- The leaders of both the Conservatives and New Democrats say the prime minister needs a new system for choosing officers of Parliament.

In a joint letter, Andrew Scheer and Tom Mulcair say they want Justin Trudeau to clarify how he plans to handle other vacant positions in the wake of the controversy around his pick for official languages commissioner.

Madeleine Meilleur withdrew her candidacy this week, saying she didn't think she would be able to do the job properly given the uproar since her name was put forth by the Liberal government.

Meilleur, a former Liberal member of the Ontario legislature and provincial cabinet minister, told a House of Commons committee she'd talked to Trudeau's advisers about her interest in the job prior to the nomination, though the government disputes that.

The Liberals had said Meilleur's selection was based on merit, experience and a track record of defending francophone rights and reiterated that Thursday in defending both her and the process.

But Trudeau has tainted the process of selecting what are supposed to be completely independent officers of Parliament, Scheer and Mulcair wrote in their Thursday letter.

'Great lack of judgment'

"By attempting to appoint someone with such a highly partisan background to a position which is supposed to be free, not just of partisanship, but even the hint of being susceptible to political influence or partisan interests, you have shown a great lack of judgment on the role of an officer of Parliament and its interaction with Parliament," the letter says.

"As leaders of the recognized parties in the House, we demand that you refrain from turning such appointments, which are supposed to be non-partisan, into havens for political patronage."

The two leaders want Trudeau to follow the law and consult them about future appointments, but the Liberals offered no signs Thursday that's in the cards.

"Our government promised Canadians a rigorous, open and merit-based process for public appointments and we are keeping that commitment," Sean Casey, parliamentary secretary to the Heritage minister, said during question period.

The opposition said the Meilleur appointment could have been a watershed.

"You can bet that had this appointment occurred, the dominoes would have fallen quickly to fill the other vacant, non-partisan positions with Liberal insiders," Conservative MP John Brassard said.

Casey said more information on next steps to fill the languages commissioner position would be unveiled in the coming days.

In addition to the official languages commissioner, there are seven others traditionally referred to as "offices of Parliament," known as such for their arms-length and independent work assisting Parliament and holding government and bureaucrats to account.

The Liberals are currently looking for replacements for the access to information commissioner, the conflict of interest and ethics commissioner, the lobbying commissioner and the chief electoral officer, in addition to the languages commissioner.

The three other posts -- auditor general, commissioner of public integrity and privacy commissioner -- have a few years left on their terms