The opposition says it is startled by the insistence by the Prime Minister's Office that there's little chance Stephen Harper will have to testify at Sen. Mike Duffy's criminal trial.
"It's remarkable that the prime minister's office has decided that they would comment on this matter before the courts when they normally do not comment on matters before the courts," Liberal MP Geoff Regan told an Ottawa news conference.
"In my view, it's a matter for the courts to determine whether or not Mr. Harper should testify."
Jason MacDonald, a spokesman for Harper, said on Tuesday it was "difficult to imagine" the prime minister testifying because the RCMP have made it clear they don't believe the prime minister has any knowledge of Duffy's alleged wrongdoing.
In an email, he added there would be no reason for the prime minister to be involved should Duffy's defence team attempt to call him to the witness stand.
The NDP's Peter Julian said he suspects the PMO, via MacDonald, is trying to send a message to the courts about Harper's reluctance to testify.
"I think he's flagging it in a subtle way," Julian said in an interview.
"His office seems to be indicating that he's not going to be forthcoming and I think that's a big mistake. Canadians have a strong expectation that Mr. Harper is going to start answering questions."
'Yet another conspiracy theory from the NDP': PMO
MacDonald took issue with that interpretation on Wednesday.
"This is yet another conspiracy theory from the NDP that completely misconstrues my response," he said in an email.
"In any case, the prime minister had no knowledge of the wrongdoing Mike Duffy has been charged with. The RCMP itself has made clear they don't believe he had any knowledge or involvement in it and we see no reason to expect that the PM would testify, given this."
The RCMP announced last week it was charging Duffy with 31 criminal counts related to his expense claims, accusing him of misspending more than $200,000.
The charges stem from the disgraced senator's housing and travel expenses, and a $90,000 payment from Nigel Wright, Harper's former chief of staff.
How much Harper knew about the clandestine payment made by Wright is likely to come up during court proceedings.
The lead RCMP investigator has said he "is not aware of any evidence that the prime minister was involved."
Earlier this week, a new court filing provided fresh details of the RCMP's charges against Duffy, alleging he billed taxpayers for a personal trainer, a makeup artist and for personal travel to funerals.
Neither Duffy nor his lawyer have responded to a request for a comment on MacDonald's comments.
The 68-year-old senator is scheduled to appear in court on Sept. 16, and has denied any criminal wrongdoing.
Liberals call on ethics watchdog to reopen investigation
It's been a trying few days for Duffy.
The lawyer for a 32-year-old Peruvian woman who claims she is Duffy's "love child" says the former CTV newsman reached out to her this week.
Jorge Alejandro Razuri said on his Facebook page that Duffy has been in touch with Karen Duffy.
It wasn't immediately clear if that meant her court action against him to establish paternity has been dropped.
"Out of respect for the parties we will not be making any further comments or statements at this moment," Razuri wrote.
The Liberals are calling on the federal ethics watchdog to re-open her investigation into the Senate expense scandal, a scenario Mary Dawson's office suggested wasn't on the immediate horizon.
Regan wrote to the ethics commissioner, saying it is time for a renewed probe now that Duffy has been formally charged.
Dawson had launched an investigation last year, but suspended it when the Mounties announced their criminal investigation.
But a spokeswoman for Dawson said the commissioner wasn't yet prepared to re-open her investigation.
In April, the RCMP concluded there wasn't enough evidence to charge Wright, who resigned after it was revealed that he provided Duffy with the money to help him cover his expenses.