As Senators prepare to consider a motion at 2 p.m. ET today that could force their embattled colleague Patrick Brazeau to take an imposed leave of absence, the Senate's leadership has decided to come down hard on all senators who may be claiming expenses to which they're not entitled.

Conservative Senator Marjory LeBreton, government leader in the Senate, and Liberal Senator James Cowan, opposition leader, released a letter jointly Monday noting that the Senate's board of internal economy has asked all senators who claim expenses for maintaining a secondary residence in Ottawa to provide copies of their health card, driver's licence, income tax return and a declaration stating where the senator votes.

And the letter — addressed to the board's chair and deputy chair — goes on:

"Should any senator be unable to convince you that the claim is valid, that senator should be required to repay immediately all monies so paid with interest."

The same board asked last week for an outside audit to examine whether the living and travel expenses that three senators have been charging are legitimate.

Conservative Patrick Brazeau and two others, Conservative Mike Duffy and Liberal Mac Harb, will be audited by Deloitte Canada. The three have claimed expenses for maintaining a secondary residence in Ottawa, or in Brazeau's case, in Gatineau, on the grounds that they live more than 100 kilometres outside the capital.

Secondary residence in Ottawa

Duffy has been claiming that his primary residence is in P.E.I., while Harb claims a house near Pembroke, Ont. as his primary residence. Brazeau has been claiming his father's address in Maniwaki as his primary residence, though he lives in Gatineau, a short distance across the river from Parliament Hill.

Duffy, a former TV reporter, has lived in Ottawa for years and has owned a house in the Ottawa suburb of Kanata for the past decade. Harb is the former MP for a downtown Ottawa riding and owns several properties in the city.

In Question Period on Monday, opposition MPs demanded to know if other senators were claiming expenses they may not deserve. "Are there any other senators who've been breaking the rules and ripping off the taxpayers?" asked New Democrat Charlie Angus.

Government House Leader Peter Van Loan replied, "The Senate has been looking into this matter, are reviewing these matters, something we've encouraged as a government, and I suspect they will complete that process in a thorough and diligent fashion."

The letter to Conservative Senator David Tkachuk and Liberal Senator George Furey, the chair and deputy chair of the board of internal economy finishes by saying:

"We believe it is vital for the reputation of the Senate and those senators who are in full compliance with our rules and regulations that this determination be made as soon as possible and that the results be made public."

In the publication Hansard, which is a record of Senate and Commons debates, Brazeau's post office address in 2010 was listed as Gatineau and Harb's as Ottawa, which raises questions about why both senators were approved for living and travel expenses based on claims that they live at least 100 kilometres outside Ottawa.

An examination of some other expense claims of senators who lived in Ottawa before their senate appointments — such as LeBreton herself, Colin Kenney, Jim Munson and Vern White — indicate that they have never claimed anything in expenses for secondary residences.

Brazeau may go on forced leave

The Senate will move a motion Tuesday which, if it passes, would put Brazeau, who was charged Friday with assault and sexual assault that allegedly occurred in his Gatineau home, on forced leave of absence.

The motion would allow Brazeau to collect his senate salary, but he wouldn't be able to charge for travel or spend any other Senate money. In addition he wouldn't be able to take his seat in the chamber.

The motion stops short of the outright suspension of Brazeau's salary. LeBreton explained in a statement Friday: "Obviously, he cannot be removed immediately, because of the presumption of innocence, and will continue to be paid."

The criminal charges against Brazeau came during a week that had already damaged Senate's reputation and revived sentiments about abolishing the Senate altogether.

Only once before has a senator been stripped of his or her perks and privileges. In 1998, the Senate voted to eliminate the ability of Liberal Senator Andrew Thompson to claim any expenses. Thompson had moved to Mexico and only showed up for a few days during each session. Records showed that he had attended the Senate only 47 times in 14 years.

Later, the Senate suspended Thompson's pay after he refused to appear and explain his chronic absenteeism. A month later, the 73-year-old Thompson, a Trudeau appointee, resigned and was able to start collecting his senate pension.

Thompson always maintained that he was too ill to travel to Ottawa.