The Opposition is blasting Prime Minister Stephen Harper for not speaking out publicly about the damning audit of Sen. Pamela Wallin’s expenses, even though he defended her earlier this year when allegations of misspending began to surface.

NDP MP Paul Dewar said the audit’s finding that Wallin claimed more than $120,000 in improper expenses shows “the poor judgment” of the prime minister who appointed her to the Senate in 2009.

An independent audit released by Deloitte showed Wallin had claimed travel expenses for business-related trips and partisan fundraisers, as well as regular stops in Toronto while flying between Ottawa and Saskatchewan, her home province.

Wallin was ordered Tuesday to repay $121,348, plus interest. She has already repaid $38,369 of the ineligible claims, so she must pay back the outstanding balance.

Another $20,978 of the senator’s expenses was deemed “subject to interpretation” and was being reviewed. A Senate source said it has yet to be determined how much, if any, of that figure Wallin may have to repay.

In February, Harper stood up in the House of Commons and defended Wallin’s travel expenses. 

“I’ve looked at the numbers. Her travel costs are comparable to any parliamentarian travelling form that particular area of the country (Saskatchewan) over that period of time,” he said.

On Wednesday, a spokesperson for Harper said that Wallin, who is no longer in the Conservative caucus, “must be held accountable for her actions.”

Members of the Liberal Party also criticized Harper’s handling of the Wallin affair and the Senate spending scandal.

Liberal MP Stephane Dion said many of the costs associated with the ongoing Senate expense scandal could have been avoided if Harper would "send the right messages."

"He's sending the message that if you're not caught, it's OK," Dion said, adding that Harper has created a "culture of secrecy."

"The prime minister staying mute about all these issues is sending the wrong message," he said.

Sen. James Cowan said greater transparency in both the Senate and House of Commons must be put in place when Parliament resumes its work this fall, vowing that stricter rules regarding expenses will be in place for Liberal senators and MPs. "It's not enough anymore to simply say Senate business (on expenses)," he told reporters in Ottawa.

Cowan noted Wednesday that the Deloitte audit ended up costing taxpayers $127,000 -- more than the amount Wallin has been asked to pay back -- but the Liberal senator said it was "a cost worth spending."

"I think we will learn from this,” he said. “There may be some changes that are necessary in our rules and procedures as a result.”

The audit has been referred to the RMCP, which Cowan said was the right body to investigate the matter.

But Sen. Hugh Segal, one of Wallin’s supporters, said he doubts the Mounties will lay criminal charges against the Saskatchewan senator.

“(The Senate) feels that if they’ve said (the audit) needs to go to the RCMP…they’ve indicated that they’re appropriately concerned,” he said.

In a bid to increase transparency, Liberal Leader Justin Trudeau announced in June that travel and hospitality expenses for Liberal MPs, senators and staff will be released online on a quarterly-basis.

"We hope members of other parties will follow us," Cowan said of those changes. 

The audit into Wallin’s expenses came three months after audits into the expense claims of Sen. Mike Duffy, Sen. Mac Harb and Sen. Patrick Brazeau were released. All four audits are now being probed by the RCMP.

With a report from CTV’s Omar Sachedina and files from Christina Commisso