Sen. Mike Duffy is trailed by media as he arrives at the Senate on Parliament Hill in Ottawa on Tuesday, Oct. 22, 2013. Sean Kilpatrick/Canadian Press
Senator Mike Duffy's testimony in the Senate on Tuesday puts the onus on the prime minister to explain his office's response to the Senate expenses scandal, NDP Leader Tom Mulcair told reporters after a meeting with his caucus on Wednesday.
"This is a profound scandal that directly implicates Stephen Harper," Mulcair said in a scrum on Parliament Hill.
Liberal Leader Justin Trudeau will speak at 12:30 p.m. ET. CBC.ca will carry Trudeau's remarks live.
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The Conservative caucus is also meeting Wednesday morning.
On Tuesday, Duffy, the former Conservative senator, spoke publicly for the first time in months, following a summer of allegations in RCMP court documents that he misspent Senate funds.
Duffy alleges Prime Minister Stephen Harper ordered him to pay back his questionable expenses .
Nigel Wright, Harper's former chief of staff, then arranged to repay Duffy's questionable expenses — a total of $90,000.
Duffy also named names of people involved in negotiating the alleged arrangement and in putting pressure on him, he says, to repay the expenses.
Duffy says he hasn't done anything wrong and that his housing claims, some of the spending for which the RCMP are investigating him, are above-board.
Each party meets every Wednesday when Parliament is in session, leading to raucous question periods afterward. CBC News will have question period live.
Senator Patrick Brazeau, who has also been hit by the spending scandal, spoke to the Senate on Tuesday. Senator Pamela Wallin will speak to the Senate this afternoon.
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