Former Supreme Court justice Ian Binnie has been named by the Senate to arbitrate disputes arising out of the auditor general's investigation into senators' expenses — even in cases where the file has been referred to the RCMP.

Speaking with reporters Tuesday after announcing the appointment, Senate Speaker Housakos confirmed that "every single case" — including those expected to be referred to the RCMP or other law enforcement agencies for criminal investigation — can be appealed to the new arbiter.

"Arbitration will be available to senators, both current and former, who disagree with the findings of the auditor general," Housakos told reporters.

"Any case where there are disagreements will have the arbitration, including those referred to the RCMP."

RCMP will take priority: Binnie

In response to a question from Power & Politics host Evan Solomon, Binnie stressed an RCMP investigation would have "clear priority" over the arbitration process.

"The law is clear that arbitrators don't get in the way of the police," he told Solomon.

"Criminal matters always take precedence over civil matters."

Until now, disagreements over expense claims were handled entirely by the Senate's internal economy, budgets and administration committee, which conducts virtually all its business in secret.

"The appointment of an independent arbitrator ensures that questions of reimbursement will be dealt with in a timely and fair fashion," Housakos said Tuesday.

"All decisions by the special arbitrator and [the senate internal economy committee] will be made public, in line with our commitment to transparency and accountability," Housakos said, calling the new dispute resolution process "another step towards our modernization" of Senate rules and practices.

'Lots of flexibility' in arbitration

"I am satisfied that this procedure is independent, fair and impartial," Binnie said in a statement.

"Every citizen has the right to due process. The Senate arbitration process ensures this."

Senators linked to controversial expenses in an upcoming auditor general's investigation will deal with former Supreme Court justice Ian Binnie, now named as an outside arbiter. (Chris Wattie/Reuters)

Now-retired senators who appeal will have to sign an agreement to accept the decision as binding. Unlike with sitting senators, there's no ability to garnishee wages to repay wrongful expenses.

And while Binnie's decisions will be referred to the internal economy committee, that will be for "execution ... not discussion," according to Senate spokeswoman Nancy Durning.

"I take 'execution' to mean implementation, not re-adjudication," Binnie told Solomon.

Beyond that, however, he said there wasn't much more to say at the moment.

"The parties — the committee and the senator, respectively — will have a say on how they think I should proceed in any particular case."

Binnie backed Nadon appointment

This isn't the first time Binnie has been brought in to handle a potentially politically sensitive file.

Before its ill-fated attempt to install Marc Nadon on the Supreme Court in 2013, the government paid him $7,463.65 to answer the question: "Is a sitting judge of the Federal Court qualified for appointment to the Supreme Court as a Quebec member," if he or she practised law in Quebec for at least 10 years prior to becoming a judge?

Although Binnie concluded that Nadon was qualified, his appointment was immediately challenged by Toronto lawyer Rocco Galati, who eventually succeeded in persuading Binnie's former colleagues on the bench to declare him ineligible on constitutional grounds.

The committee's handling of disputed claims took a beating last month at the fraud and breach of trust trial of suspended senator Mike Duffy.

Defence lawyer Donald Bayne suggested New Brunswick Senator and former Stephen Harper aide Carolyn Stewart Olsen shouldn't "sit in judgement" of Duffy on his residency and housing claims while her own residency status was also in question.

Speaker wants secret report blocked

Housakos was also questioned about the Upper House's refusal to disclose the contents of an internal investigation into the residency status of all then-current senators. That report, which was conducted by a Senate staffer at the behest of the Senate internal economy in late 2012, has never been released publicly.

Duffy's legal team has launched a court fight to force the Senate to produce the documents, which its lawyers have asserted is protected by parliamentary privilege. That case is expected to be heard by Ontario Superior Court Justice Charles Vaillancourt when Duffy's trial resumes next week.

While Housakos told reporters that he hasn't personally seen the report, he said it contains "private information" such as email addresses and phone numbers.

"You wouldn't want that information made public, so why should we make senators' [public]," he said.

Auditor General Michael Ferguson is set to release findings from his investigation into Senate expenses next week — two years after he first began what was expected to be an exhaustive review.

Sources told CBC News earlier this month that the audit has found "a few people with big issues."

A flow chart accompanying the announcement lays out the proposed arbitration process in detail: