Funding for a £400 million media centre for the London Olympics is in doubt because of restrictions on lending in the financial markets, The Times has learnt.

The broadcast and press centre, which will play host to 20,000 journalists during the Games in 2012, is the second casualty in the £9.3 billion Olympics project of the credit crisis, which has led banks to rein in their lending, particularly for property-backed deals.

Olympics bosses are already struggling to raise money from the private sector to fund the £1 billion athletes' village, the biggest component of the 500-acre Olympic Park in East London. It has emerged that they are also concerned about the ability of Carillion Igloo, the consortium awarded the contract to build the media centre, to raise money from banks to cover its £200 million share of the cost. A senior Olympics source said: “It's difficult because, in this climate, no one wants to lend.”

Without private financing, the Government would be forced to raid a £1 billion contingency fund set up for unforeseen events.

This emergency money is part of the £9.3 billion budget that ministers vowed would be the ultimate cost to taxpayers of the Olympics. But consuming most of it with nearly four years to go until the Games would leave the Government with little room for manoeuvre should other parts of the budget, such as security, begin to spiral.

Construction of the media centre, two buildings designed to provide 1.3 million sq ft of office space after the Games, is scheduled to start in the spring. The next three months will be crucial if the Olympic Delivery Authority (ODA), the public agency responsible for building the venues, is not forced to go cap in hand to the Government.

Alistair Darling, the Chancellor, would be loath to approve the release of money from the contingency fund at such a politically sensitive time. The next Games funders' group meeting is next month. ODA executives hope to avoid the need for seeking money from the contingency fund by securing financing agreements with both Carillion Igloo and Lend Lease, the Australian developer building the athletes' village, by Christmas.

Lend Lease had been expected to provide £450 million alongside a £550 million public contribution from the ODA but its banks, led by Barclays, Lloyds and RBS, have got cold feet about financing a deal based on speculative property valuations.

The ODA hopes to recoup £250 million once the site is converted into a residential development with 3,500 homes but, with property prices declining fast, those involved find it impossible to agree on what values might be in 2013. However, as the village contains an “affordable housing” element, some of the funding gap could be plugged by housing associations.

“The reality is that the situation is changing by the day,” John Armitt, the ODA chairman, told a fringe meeting at the Labour Party conference in Manchester on Monday. “The amount of financing available two months ago was less than six months ago and it's even less after last week.”