The cost of fitting out the London Olympic Stadium ahead of Premier League football club West Ham's move to the venue will rise by £35.9 million ($57.7 million, 45.6 million euros), it was revealed Wednesday.

However, officials stressed the increased cost would not be paid either by the taxpayer or West Ham.

The stadium, centrepiece of the 2012 Olympic Games, is due to stage five matches at next year's Rugby World Cup before West Ham move there from their nearby current Upton Park home to make the venue their permanent home in time for the 2016/17 season.

The stadium, the cost of which was a source of much public debate in Britain before the Games, was built for £429m and an additional fixed conversion fee of £154m was then agreed with constructors Balfour Beatty.

That figure, however, has now risen to £189.9 million due to difficulties in strengthening and extending the stadium's roof.

"Providing adequate support for the new roof has required significantly more strengthening work to the main roof truss, which was originally designed to be taken down after the Games," a statement on queenelizabetholympicpark.co.uk read.

"We have therefore today (Wednesday) agreed to increase the value of the Balfour Beatty contract by £35.9 million to £189.9 million."

However, the statement insisted: "We will meet these costs from the project contingencies and additional income we will generate from our other developments.

"There will therefore be no additional call on the taxpayer and no impact on our current programme."

Despite the total bill for the renovated 50,000-seat stadium, now just shy of £619 million, West Ham will contribute just £15 million for a 99-year lease together with annual rent and a share of income following an agreement they made last year with the London Legacy Development Corporation, chaired by London mayor Boris Johnson.