A Liberal and two Conservative senators have repaid dubious expense claims which were detailed in a special arbitrator's report.

Senate records show Sen. Colin Kenny has paid almost $31,400 in expenses that former Supreme Court justice Ian Binnie deemed unjustified in his report released last month.

Binnie found that the questioned trips included overnight stays that didn't appear necessary and were sometimes scheduled around holidays with friends, time with family and even a suit fitting in Toronto.

Kenny's expenses were first flagged by the auditor general last year and sent to the RCMP for review.

Kenny says he won't make any comment until a final resolution of all issues.

Staffer trips expensed

On Wednesday, Conservative senators Jean-Guy Dagenais and David Tkachuk, the former chairman of the Senate committee that oversaw the spending rules, paid back money Binnie said they shouldn't have charged taxpayers.

For Dagenais, that meant repaying almost $2,300 for expenses that included trips a staffer wasn't eligible to claim. And for Tkachuk, it meant repaying $1,900 for trips that included a November 2011 flight to Ottawa from Saskatoon that Binnie said was primarily for Tkachuk's work on a corporate board.

Former Supreme Court Justice Ian Binnie released a report into disputed senator expenses last month after reviewing 14 files. (Adrian Wyld/Canadian Press)

The repayments leave 12 current and former senators still on the hook for more than $622,000 in improper expenses first flagged by the auditor general last June.

Current senators who don't pay up before April 22 will have their salaries clawed back until their debt is repaid, while former senators who fail to repay will be taken to court by the Senate.

The arbitration process was established after a report released last June by auditor general Michael Ferguson raised questions about nearly $1 million in expense claims from 30 current and former senators. Nine senators, including Kenny, had their files sent to the RCMP for review.

Not 'gaming the system'

Binnie was appointed as arbitrator last May to oversee those cases involving senators who disputed the auditor's findings.

In releasing his final report last month, Binnie said he didn't feel any of the 14 senators he judged were "gaming the system." Instead, they simply didn't think through whether an expense was reasonable.

What the majority of offenders were doing, he said, was mixing personal business with Senate business in order to better justify their travel claims.