The Prime Minister鈥檚 Office says the RCMP has not asked it for an email detailing a $90,000 payment to Sen. Mike Duffy from Stephen Harper鈥檚 former chief of staff.

CTV News reported Tuesday that the PMO has been withholding the email, but the office says that鈥檚 not true.

Spokesperson Julie Vaux said Wednesday 鈥渙ur office has not been asked for this email,鈥 but also said the PMO is assisting the RCMP investigation into the $90,000 cheque Nigel Wright wrote to Duffy to cover the senator鈥檚 improperly claimed living expenses.

The Feb. 20 email describes the secret deal between Harper鈥檚 former right-hand man and Duffy, whose spending and residency claims were being audited.

CTV News first revealed the contents of the email two months ago. The prime minister鈥檚 communications director, Andrew MacDougall, recently confirmed to CTV鈥檚 Ottawa Bureau Chief Robert Fife that the email exists.

MacDougall said Wednesday that 鈥渨e stand ready to provide any and all assistance or information requested.鈥

CTV News has confirmed that the RCMP interviewed Senators Marjory LeBreton and Carolyn Stewart-Olsen earlier this month as part of its ongoing investigation into the Senate expenses scandal.

Former RCMP Supt. Garry Clement said the Mounties could obtain a search warrant if the PMO does not hand over the email.

鈥淭he PMO is not sacrosanct, and therefore, a warrant issued properly by judicial authority, they have to co-operate,鈥 he told CTV.

In the email, Duffy tells his lawyer that Wright worked out a 鈥渟cenario鈥 where all of the senator鈥檚 invalid expenses would be covered, including 鈥渃ash for the repayment,鈥 and the government would use its influence to blunt the outcome of the external audit.

A Conservative-dominated Senate committee subsequently edited the original audit of Duffy鈥檚 expenses to remove damning findings.

Amid the controversy, Wright resigned and Duffy left the Conservative caucus.

RCMP affidavits allege that three other senior PMO staffers knew about the Wright-Duffy deal.

Harper has maintained that Wright acted alone when he wrote a cheque to the embattled senator.

On Wednesday, the opposition criticized the PMO for its statements about the email.

鈥淚nstead of engaging in this proactive disclosure, they seem to be hiding behind weasel words like, 鈥楴o one asked for this particular email,鈥欌 NDP MP Jack Harris told CTV. 鈥淭here鈥檚 something wrong with that.鈥

Liberal Leader Justin Trudeau said he hoped an RCMP investigation would produce 鈥渟ome answers on this, but we see this government prefers to choose secrecy, cover up and spin.鈥

With a report from CTV鈥檚 Richard Madan and files from The Canadian Press