Conservative Senator Pamela Wallin admitted Wednesday she has met with the auditing firm Deloitte to review her travel expenses.

Deloitte was hired by the Senate to investigate the travel claims and living expenses of four senators. Besides Wallin, Conservative Patrick Brazeau, Conservative Mike Duffy and Liberal Mac Harb are being audited. There is some question about whether the senators really live in the area that they claim is their primary residence. All have filed expenses for having to maintain a second residence in or near Ottawa.

When the Senate announced the audit last week, no mention was made of Wallin.

After reports said Wallin was also being questioned, she circulated an email to the media, saying "I certainly did willingly meet with a representative from Deloitte to review travel expenses and I answered all questions and have provided all the necessary information regarding claims."

One media report stated that Wallin had offered to give back money to the Senate. But, she said, "No offer of repayment was made or asked for."

Wallin added that she spent 168 days in Saskatchewan last year, calling it her home province.

It has been suggested that Wallin, who was named to the Senate by Prime Minister Stephen Harper in 2008 to fill one of Saskatchewan's slots, does not really live in Saskatchewan, but in Toronto where she owns a condo.

Before her Senate appointment Wallin lived in Ottawa, then in Toronto for a time, where she worked for CBC and CTV, and in New York where she was Canada's Consul General.

'My heart is in Wadena'

Wednesday in an op-ed in the Globe & Mail, Wallin attested to her residency in Saskatchewan, writing, "My heart is in Wadena, Sask., and so is my home. Wadena is where I reside in my home province... I spend every possible minute I can at my home in Wadena or at my cabin at Fishing Lake during the summer."

Wallin has claimed about $29,000 in "regular travel"— meaning to and from — and about $321,000 “other” travel since Sept. 2010. "Other" travel is for Senate-related business and could include speeches, special events or even trips to international locations that stem from her position as chair of the Senate's National Security and Defence Committee.

Howard Leeson, a professor at the University of Regina who has also worked as an advisor for two NDP premiers in Saskatchewan, has done his own analysis of Wallin's flights to Saskatchewan, and has found that in 2011-12 the money Wallin records for the trips in her expense forms is considerably less than amounts for the other five Saskatchewan senators.

Wednesday, Wallin explained to a private radio station why it might appear that not all her ''regular” travel was to Saskatchewan. She said there are no direct flights between Ottawa and Saskatoon, so she often flies to Toronto, overnights in her condo, and then takes the first morning flight to Saskatoon. Those steps, she said, saved her from a two-and-half-hour late-night drive to Wadena and also could potentially save taxpayers the cost of a hotel in Saskatoon.

The trouble is, she went on to say, is that the Senate doesn't recognize a Toronto to Saskatoon ticket as a "regular flight" because it originates in Toronto, not Ottawa. The same problem occurs, she said, if she is at a Senate-related event in Halifax, and then flies home from there to Saskatoon.

Wallin told CBC Radio Wednesday, "Because I do so much public speaking and other events, I end up with most of my trips to Saskatchewan falling into the 'other' catergory because they don't necessarily orginate right at that minute in Ottawa."

PM says Wallin spends 'half her time' in Saskatchewan

Wednesday in question period, when asked by the opposition about Wallin's travel claims, the prime minister replied that Wallin's expenses were comparable to other parliamentarians who had to travel the same distance. He added that last year Wallin had spent "half her time" in the Saskatchewan.

Leeson has written to the Senate more than once, complaining that Wallin is not a resident of Saskatchewan. In a recent letter to Senator David Tkachuk, who heads the Senate's Board of Internal Economy, its self-governing body, Leeson writes, "To my knowledge Ms. Wallin has not lived continuously in Saskatchewan for a number of years. As well, she does not meet the ordinary residency requirements as a set out in a number of provincial and federal regulations."

Leeson goes on the point out that regulations in Saskachewan stipulate that a provincial voter or a holder of a Saskatchewan health card must spend six months a year in the province, a requirement he does not believe Wallin can fulfill.

In her interview with a private radio station Wallin said that she collects her mail from the post office in Wadena.

The government and opposition leaders of the Senate have urged the Senate's internal economy board to have all senators who live outside the Ottawa region prove their primary residence by providing health cards, driver's licences, as well as a declaration of where they vote, and where they pay provincial income tax.

Wallin told CBC Radio that the only constitutional requirement for a senator to prove residency is that he or she own a piece of property in the province. She didn't directly answer a question about whether she has a Saskatchewan driver's licence, but said that residency rules for senators should be modernized.