Concerns were raised over the financial viability of UK offshore wind projects at the weekend, as it emerged that Centrica was reviewing the economic case for 1,000MW of planned turbine construction and Statoil began the search for a new partner for its 315MW Sheringham Shoal project after Ecoconcern pulled out.

Rising construction costs and the current squeeze on credit are being blamed for the moves, which are the latest in a series of indications that some project developers are rethinking their commitments to offshore wind.

On Friday, energy firm Centrica told newspapers that it was "revisiting the economics" of a proposed £800m 250MW wind farm off the east coast, as well as two further proposed projects at Race Bank and Docking Shoal.

The company said the cost of investment in offshore wind power had risen to about £3m for every megawatt of installed capacity, up from estimates of about £2m per megawatt earlier in the year.

Last month, Centrica announced a £2.2bn rights issue, but that money is earmarked to help fund the company's planned acquisition of 25 per cent of nuclear power company British Energy, as part of an expected deal with the nuclear operator's new owner EDF.

Meanwhile, it has also emerged that Norwegian oil firm Statoil is looking for a new partner to help develop a proposed £700m offshore wind project at Sheringham Shoal off the Norfolk coast after previous partner Ecoconcern pulled out, citing financial concerns.

The British Wind Energy Association (BWEA) attempted to downplay the significance of the news, which follows announcements earlier this year from BP and Shell that they will not invest in the UK offshore wind sector, arguing that projects would inveitably change hands in any emerging market.

"This is a cost hump rather than a long-term trend and it is natural for companies to review projects when this is the case in the current climate," he said.

The BWEA is also predicting that installation costs will fall in the medium to long term as the market becomes more mature.

"We're going from no market at all to a planned 40GW of capacity in North Europe," the spokesman said. "As commodity prices come down, more companies will come into the market and offshore wind will become cheaper to install."

There is considerable evidence to back up BWEA's view that the sector will continue to attract investment.

Almost 100 companies have already expressed an interest in bidding for the licences to develop the next wave of offshore wind farms, and where companies have looked to offload projects others have been quick to step into the breach.

For example, earlier this month German energy firm RWE bought a 50 per cent stake in Scottish and Southern Energy's £1.3bn offshore wind farm, at Greater Gabbard off the Suffolk coast, while last week Swedish firm Vattenfall acquired the £800m Thanet wind farm project from the Christofferson Robb hedge fund.

Abu Dhabi's Masdar soveriegn wealth fund also acquired a 20 per cent stake in the London Array project earlier this year after Shell's high-profile decision to exit the project.