Speaking at the weekend energy minister Greg Barker told the he was confident that proposed subsidy levels - which would see support cut by 13% over the next five years - were high enough.
The Committee on Climate Change, wrote to Decc’s Energy Secretary, Ed Davey, warning him that the "required investment is at risk under current proposals."
In 2014-15 Decc propose subsidies of £155 per MWh of electricity generated over a 15-year contract for offshore wind, dropping to £135 per MWh in 2018-19.
David Kennedy, CCC chief executive, said: "I have spoken to every major investor and they are all concerned."