The committee, which oversees the upper chamber's internal budgets, has asked the Deloitte accounting firm to review the residency claims of Conservative senators Patrick Brazeau and Mike Duffy and Liberal Mac Harb.
The accountants will look at their claims about where they live and their related expenses.
Duffy is a senator for Prince Edward Island, Brazeau holds a Quebec seat and Harb, a longtime former Ottawa MP, sits for Ontario.
Committee chair Sen. David Tkachuk and deputy chair Sen. George Furey are also seeking a legal opinion on the question of Duffy's residency, says a news release.
In a statement today, Duffy insisted he has done nothing wrong.
"As a Prince Edward Islander, born and bred, I am proud to represent my province and its interests in the Senate of Canada," Duffy said in the statement.
"I represent taxpayers with care, and Canadians know I would never do anything to betray the public trust. I have a home in Prince Edward Island as required by law. I will have no further comment until this review is complete."
Meanwhile, Brazeau appeared today in a Gatineau, Que., court on charges of assault and sexual assault. He is to be released on bail with a number of conditions and is expected to return to court next month.
Police arrested the controversial senator Thursday at his home just across the river from Parliament Hill following a 911 call.
Prime Minister Stephen Harper swiftly expelled Brazeau from the Conservative caucus. He intends to remain in the Senate as an independent, his office says.
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