The delay raises the prospect of an entire summer passing before the full Senate would be able to vote on any action against Wallin.
Conservative Senator David Tkachuk told CBC News he has yet to receive a definitive answer as to when the audit will be complete, but said it now appears it will be some time after the Senate rises for the summer.
"I am hoping it would have come in at the end of June but it doesn't look that way," Tkachuk told the CBC's James Cudmore.
"So, we are trying to get a more definitive date than this summer, right? So that's all we're trying to get right now."
The internal economy committee that Tkachuk chairs can continue to sit in the summer, even if the full Senate is on summer break.
But it would not be able to table its report until Parliament resumes. Both the Senate and the House of Commons are scheduled to resume sitting after the summer break on Sept. 16. The Senate is scheduled to sit until June 28.
It's not clear how, or even if, the committee could make its findings public unless it is able to table a report.
"It's not a mess, it just makes it more difficult," Tkachuk said. "We will deal with it in internal [economy committee], and then we'll table the report as soon as Parliament meets."
That delay may make life less difficult for the subject of the audit. CBC News has learned Wallin has already repaid more than $40,000 in potentially improper expense claims.
But it's expected the total repayment required could be more than that. A delay would potentially give Wallin more time to deal with any debt.
The Saskatchewan senator resigned from the Conservative caucus and will sit as an Independent until the audit into her expense claims is completed.
It is possible for the government to call back the Senate over the summer months — in fact, the government has already threatened to do that in order to force the Upper Chamber to approve a bill that would force unions to publicly disclose more of their financial information.
That private members' bill is popular with the Conservative backbench, and the government wants to see it through the Senate before the fall.
Prime Minister Stephen Harper is widely expected to prorogue Parliament at some point before the fall so it can be reconvened with a new agenda-setting throne speech.
It's not clear when precisely a prorogation would occur, but if it does, it would have the effect of shutting down not just the House of Commons, but the Senate and most of its committees too.
Tkachuk said the internal economy committee would survive a prorogation and could continue its work whether or not Parliament is convened.Suggest a correction