The Tories are insisting their finances are "in good shape" despite reports of a record hole in their funds.
The Tories think they can net £30m from selling their old HQ
The Times newspapers says the latest Conservative accounts will show they are running a £30m deficit.
A Tory spokesman said the figure was wrong and the real deficit was much lower, but declined to reveal the correct amount.
"No one is denying that last year's general election campaign cost the party a great deal," he said.
"However, today the party's finances are in good shape and improving day by day. For example, our debt has been dramatically reduced, and we now own the freehold of 32 Smith Square."
Friday is the deadline for political parties to give their accounts to the Electoral Commission, although the watchdog will not publish the details until the end of July.
The Times says the accounts will show payments totalling £2m to companies owned by advertising guru Lord Saatchi, who was party chairman during the election campaign.
They will also include £7m of loans from wealthy backers, such as ex-party treasurer Lord Ashcroft, which are due to be repaid at a commercial interest rates.
The party has refused to name two supporters which previously lent it money. Their loans were repaid to preserve their anonymity.
Former senior civil servant Sir Hayden Phillips is looking into the future of party funding in the wake of claims that some donors received peerages in return for loans or gifts.
All the political parties, and the businessmen involved, have rejected the allegations.