The federal Conservative Party is denying the existence of a secret fund in the Prime Minister’s Office controlled exclusively by Stephen Harper’s chief of staff.

The CBC reported Thursday that Harper's former chief of staff, Nigel Wright, had control of a secret fund when he cut the now infamous $90,000 cheque to disgraced Senator Mike Duffy to repay ineligible Senate expense claims he made.

CBC News stands by the story.

The NDP on Friday wrote to Elections Canada asking for an investigation to determine whether the fund violates the Elections Act.

Nigel Wright resigned as Prime Minister Stephen Harper's chief of staff five days after it was made public that he had written a $90,000 personal cheque to repay Senator Mike Duffy's expense claims. (Adrian Wyld/Canadian Press)

The report quoted sources saying the money in the fund comes from Conservative Party coffers, and at times has reached almost $1 million.

On Friday, the party issued a statement that said: "The CBC claimed there is a 'secret' Conservative Party fund run by the PMO. This is false."

But the party had no such denials on Tuesday when CBC sent Conservative spokesman Fred DeLorey an email asking for details about "the special discretionary CPC [Conservative Party of Canada] fund controlled by the PM's chief of staff."

CBC had already confirmed the existence of the fund from other sources, and the email clearly identified it as money used for partisan purposes.

The email asked DeLorey six specific questions about "the special discretionary CPC fund."

Why was this "special fund" necessary?

What was it used for during Wright's tenure?

Approximately how much money was allocated to it each year?

Are there any limitations on how these funds can be spent (or is it entirely the chief of staff's discretion)?

How are these funds accounted for?

And finally:

Is there any reason those funds could not have been used in the Duffy-Wright deal?

DeLorey’s entire response was two lines.

"The prime minister at times incurs expenses that are best paid by the party."

On the question of whether the fund could have been used in the Wright-Duffy deal, Delorey said: "No funds were used for that."

Similarly, there were no denials when CBC News sent an almost identical email to Harper's communications director, Andrew MacDougall.

"I'll have to refer you to the party," MacDougall responded.

Asked whether the special fund was in any way connected to the Duffy-Wright deal, MacDougall responded: "I can give you a clear, 'no.' The funds used were Mr. Wright's personal funds."

The party's denial two days after the exchange of emails makes a number of other claims not supported by fact.

For example: "The CBC claimed party funds are hidden from Elections Canada. This is false."

In fact, Elections Canada does not oversee any political party expenditures outside an election period.

The party's press release states that "The Conservative Party ensures that non-government activities undertaken by the prime minister are never billed to taxpayers.

"The CBC is being selective, failing to mention this is a standard practice for all political parties."

In fact, all the CBC reports – on TV, radio and online – made that point clear.