The NDP won't say whether it will back a Liberal MP's motion to have the House ethics committee study Conservative MP Dean Del Mastro's 2008 election spending.

Liberal MP Scott Andrews has released a motion he's going to put before the committee on Thursday to debate a study that would see the committee call witnesses, request Del Mastro's banking records and report back next fall.

NDP MP Charlie Angus wouldn't commit to backing the motion. Andrews is the lone Liberal on the committee.

Andrews says in his motion that, since the committee can propose initiatives related to ethical standards for public office holders, the committee should call Del Mastro, his former official agent Richard McCarthy, and representatives from Holinshed Research Group, the company whose president complained to Elections Canada about Del Mastro exceeding his 2008 spending limit.

Del Mastro, the MP for Peterborough, sits on the ethics committee.

It would be difficult for opposition MPs to get the motion to pass, since the Conservatives have more members on the committee than the opposition. The committee's chair is an NDP MP, taking one more opposition vote out of the mix. Without the NDP's support, it would be impossible for the motion to pass even if some Conservative MPs weren't at the meeting.

A spokeswoman for the Conservative whip's office told CBC News she couldn't say whether the Conservative MPs on the committee would vote for or against the motion, because "committees are masters of their own domain" and the whip's office doesn't tell MPs how to vote on committees. The whip's office does, however, tell MPs how to vote in the House of Commons.

Andrews is also calling on the committee to compel Del Mastro to provide his banking records, compel McCarthy to provide related banking records and invoices, and order Holinshed to provide copies of all documents relating to Del Mastro.

Documents filed in court show Del Mastro is being investigated by Elections Canada for spending too much in his 2008 campaign. McCarthy is being investigated for accepting a $21,000 contribution from Del Mastro, which exceeded the candidates' personal spending limit of $2,100, and for submitted an incomplete election return to the agency.

'Kangaroo court'

Del Mastro has initiated several studies of his own at the ethics committee, including having former Liberal staffer Adam Carroll called for using Twitter to disseminate alleged details of Public Safety Minister Vic Toews's divorce, and studying the CBC's response to a number of access-to-information requests. He also tried to initiate a study into union sponsorship of the NDP convention, but the chair ruled that motion out of order.

Andrews pointed to the example of Carroll and said the allegations against Del Mastro are serious.

"That knife cuts both ways. You can't have it one way when it's your turn and you can't have it another way when it's someone else's turn, so one would assume they would want to get to the bottom of this and clear the air," he said.

NDP MP Charlie Angus says he'll entertain the motion, but just because Del Mastro "drags his political enemies before our committee and drags their dirty laundry out," doesn't mean the opposition should try to do the same.

"I guess my concern is that Mr. Del Mastro has turned our committee into a kangaroo court, where due process has been blown out time and time again," Angus said.

"So even though I have real questions about Mr. Del Mastro's activities, I believe he's eligible for due process."

Andrews calls that response surprising.

"This is the kind of thing our committee usually looks into," he wrote in an email. "You have to ask the tough questions in the House and get the real answers at committee."