As members of parliament return to Ottawa after a week of working in their ridings, NDP Leader Tom Mulcair will introduce a private member's bill designed to strengthen the mandate of the Office of the Parliamentary Budget Officer, CBC News has learned.

The Opposition leader will squeak in the bill in the hours ahead of a Monday evening deadline to get his PMB to the Order Paper.

As CBC reported Friday, this will almost certainly be Mulcair's only opportunity to present a bill to the House before the next federal election.

Kevin Page, the current parliamentary budget officer, was appointed by Prime Minister Stephen Harper for a five-year term that ends March 25.

Under the current legislation, the PBO is an officer of the Library of Parliament and as such has less teeth than Officers of Parliament who are independent from the government of the day.

Page has said the next spending watchdog should be accountable to Parliament in the same way that the auditor general or the chief electoral officer are.

NDP finance critic Peggy Nash has a private member's bill before Parliament – Bill C-381 titled the strengthening fiscal transparency act – that would allow for the spending watchdog to be independent.

Mulcair's bill is said to different enough that Nash will not have to withdraw hers, NDP officials say.

Appointing a successor

In January, Mulcair wrote to the prime minister asking him to extend Page's appointment until a replacement was found.

The Opposition leader pointed to the upcoming federal budget and the role of the PBO in providing information to parliamentarians and Canadians.

In February, Page told CBC Radio's The House he would agree to stay on if asked.

"I would stay on for a transition if the prime minister asked me to stay on for a few months," Page said.

Page has been criticized by the federal government for the estimated costs he gave for the proposed purchase of the F-35 fighter jet, an estimate that was later confirmed by a report from Auditor General Michael Ferguson.

He was also criticized for saying that Old Age Security was sustainable, effectively contradicting the federal government's assessment of that program.

Seen as a thorn in the federal government's side, various cabinet ministers have tried to undermine his credibility by saying the watchdog was "operating outside his mandate."

Harper has said on numerous occasions that the office of the parliamentary budget officer was created so the watchdog could do his "non-partisan work."

All eyes will be on Page's next report that will look at the joint support ship program.

The Library of Parliament is currently leading the search for a new PBO.