The prime minister spent the full £30,000 of taxpayers' money available to him to refurbish his official flat in the last financial year, Downing Street has confirmed.
Officials say no public money was spent on furniture, fittings or accessories.
It went instead on electrical works and plumbing, structural alterations, and painting and decorating.
Labour MP Tom Watson said the £30,000 grant was a "hidden bonus for the PM" for a flat he lives in rent-free.
Downing Street said any cost of renovations above the £30,000 budget was paid for by the Camerons themselves.
Earlier this week the White House released a picture of Samantha Cameron and Michelle Obama in the recently renovated flat above Number 11 Downing Street, where the PM and his family live.
The picture showed, for the first time, the newly installed kitchen.
Labour MP Mr Watson told the BBC: "Good Prime Ministers lead by example. David Cameron says the public sector should tighten belts and come clean where taxpayers' money is spent. Yet when it comes to the Downing Street flat, we see a refusal to answer even basic questions on costs. He has now been forced to admit it cost at least £30,000 to refurbish his grace and favour home - more than a policeman's salary. Are we really all in this together?"
Downing Street sources said former Labour Prime Minister Gordon Brown spent between £28,150 and £29,389 of the annual budget for refurbishing the PM's residence during his time in office.
Figures from the Cabinet Office show a total of £683,102 has been spent refurbishing and renovating Number 10 since the general election.
A spokeswoman said a modernisation programme was launched in 2006 under the last government to address structural repairs in Downing Street.
Figures for previous years show almost £1.5m was spent in 1996/1997, £1.3m in 2007/08 and £802,658 in 2001/02 maintaining the Downing Street estate, although these figures may include work on Numbers 10, 11 and 12.