The National Audit Office (NAO) has said it has “no plans” to launch a fresh investigation into the refurbishment of the Ministry of Defence’s Whitehall headquarters, despite revelations that the PFI scheme cost £2.3bn.

Tory ministers this week called for an NAO investigation into whether the scheme, which will be paid for by the government over 30 years, was value for money for taxpayers.

The call came after official figures showed that the original estimated cost of £746m would rise to £2.3bn, taking inflation into account.

The construction phase of the project, which involves the refurbishment and maintenance of the building, was completed last year.

However, an NAO spokesperson said this week that it had no plans to undertake another study into the scheme. The NAO published a report on the project in 2002, while the scheme was on site. At the time, the body backed the use of PFI, and said the deal was better than the alternatives available.

The Tories allege that the project, which includes office chairs worth more than £1,000 each, does not represent value for money. MPs have contrasted the cost with the lack of money made available for the repair and refurbishment of soldiers’ accommodation.

The scheme was delivered by the Modus consortium, which includes Laing Investments, Innisfree PFI funds and Amey Ventures. Skanska was the main contractor.