Prime Minister Stephen Harper is preparing to dump the ethics commissioner and is actively recruiting replacement candidates, CTV News has learned.

Former NDP Leader Ed Broadbent was among the government's top choices.

"The issue has been discussed with me," Broadbent told CTV. But with his wife fighting cancer, Broadbent turned down the job.

"Although I think it's a terrific job and an important job, it is certainly not one for me at this point in my life," he said.

The news of a possible shake-up comes just days after ethics commissioner Bernard Shapiro announced he would look into conflict-of-interest allegations against Harper.

Shapiro said he would investigate whether Harper breached the parliamentary ethical code for MPs by appointing David Emerson to his cabinet two weeks after Emerson won his B.C. riding as Liberal.

Shapiro said he will issue one report on the conduct of both Harper and Emerson, who is now international trade minister.

The parliamentary conflict-of-interest code prohibits inducing an MP to change his or her vote for personal benefit.

Emerson has said he would co-operate with an inquiry. However, the Prime Minister's Office has not been as open.

At the time, Harper's communications director Sandra Buckler said the prime minister is "loath to co-operate with an individual whose decision-making ability has been questioned and who has been found in contempt of the House."

Buckler was referring to the fact that Shapiro was found in contempt of the House of Commons last year when a parliamentary committee ruled that he made inappropriate comments during an interview. At the time, parliamentarians said Shapiro revealed information about an inquiry into Conservative MP Deepak Obhrai.

The PMO also accused Shapiro, a Liberal appointee, of bias.

"He's actually a Liberal appointee who has a certain pattern of attacking Conservative MPs. We find it very troubling which is why we think we should have a non-partisan ethics commissioner who reports to Parliament," Buckler told CTV.

The Tories have complained that Shapiro turned down their request to investigate Liberal Tony Valeri's landholdings during the election campaign. Shapiro said as commissioner, he couldn't act between sittings of Parliament.

Peter Julian, the B.C. New Democrat who asked the commissioner to look into the matter, said he was saddened by the response from the PMO.

"I certainly hope that he'll reconsider his position, that the reaction on the weekend was just a very strong reaction based on partisan motives," Julian told CTV's Canada AM on Monday.

He later added that Harper's decision could be seen as the wrong move.

"For him to then try in a self-serving way to say I shouldn't be investigated because I want to change the ethics commissioner's office, I think would be a political mistake and he's made enough of those in the first few weeks," he said.

Julian said he's hoping that the PMO will call a byelection in Emerson's riding.

"It's what Canadians should expect and it's what Canadians deserve."

He said that the NDP has tried to get an anti-floor crossing bill passed in parliament that would subject any member of parliament to a by-election if they considered changing parties.

"Voters across Canada voted for change on Jan. 23 and they want things to be done differently than they were done under the Liberal regime."

As for Emerson, he has apologized to his constituents, and has promised to run as a Conservative in the next election.

With a report from CTV's Robert Fife