Among the 30 current and former senators to be named in the auditor general’s report on expenses is retired Liberal senator Rod Zimmer, who is said to owe the Senate $176,000.

That’s according to Auditor general Michael Ferguson's comprehensive audit of Senate expenses, to be tabled next week.

As CTV News reported on Thursday, Ferguson is planning to refer two sitting and seven former senators to the RCMP for a criminal investigation following a long-awaited expenses audit.

The two sitting senators who will be referred to the RCMP are Pierre-Hugues Boisvenu, who left the Conservative caucus on Thursday, and Colin Kenny, originally appointed as a Liberal senator.

The other seven, all retired, are Zimmer, Don Oliver, Gerry St. Germain, Sharon Carstairs, Rose-Marie Losier-Cool, Bill Rompkey, and Marie-Paule Charette-Poulin.

Zimmer could not be reached for comment Friday. Several others defended their expense claims.

Colin Kenny said in a statement that he expects to be vindicated at the conclusion of the auditing process.

Don Oliver, a former Conservative senator, said in a statement that his expense claims are legitimate and that Ferguson’s conclusions are “not based on all the facts.”

Gerry St. Germain, another former Conservative senator, called the auditor general’s findings “baseless” and said the audit report is an incomplete record that suggests a bias or prejudgement.

In addition to the nine being referred to the RCMP, 21 other sitting and former senators will be compelled to repay questionable expenses.

Among those 21 are three senators in leadership roles – speaker Leo Housakos, government leader Claude Carignan and opposition leader James Cowan.

Carignan said a staffer misinterpreted rules on travel and has paid back $3,000 mistakenly expensed.

Housakos’ flagged expenses include $1,500 spent by a staffer who travelled to a charity event, which Housakos said has been repaid. But Housakos said he will dispute the finding that he should pay back another $6,000 spent on a contract for policy advice.

Cowan told CTV’s Power Play Friday that he will be disputing the auditor general’s finding that he should pay back $10,000. He said his disputed expenses include three trips he took in 2011 on parliamentary business, for which he filed appropriate claims supported by “appropriate resources.”

However, Cowan said the Senate did not back up his emails from that time period, so he doesn’t have the additional supporting documentation that is now required of him.

But he said he’s “perfectly satisfied” that his claims were “above board” and in accordance with Senate rules.

Senators who want to dispute Ferguson’s findings can take their case to Ian Binnie, a former Supreme Court justice who has been appointed by the Senate as a special arbitrator.

Cowan said he will respect Binnie’s decision and abide by it.

CTV News has previously reported that the Senate audit cost $21 million. That audit has uncovered $978,627 of questionable expenses. The five senators with the biggest tallies of questionable expenses owe a combined $546,000, the audit will show.

With a report from CTV’s Deputy Ottawa Bureau Chief Laurie Graham