The planning inspectorate said this week that the examination of the plan would take longer than expected given the coronavirus outbreak.
It cited its reasons as hearings being postponed and a number of interested parites not having the capacity to participate.
However the Swedish energy giant has said that delays of this length “call into question Britain’s commitment to acting quickly to reduce emissions.”
Graham Davey, Vattenfall’s Norfolk Boreas Project Manager, said: “While it’s understandable that some delay to the examination process is inevitable due to the COVID-19 restrictions, adding up to five months to the timetable is regrettable.
“In our view, all of the substantive issues in the process have already been resolved. Yet, we’re now in a position where potentially the final consent decision may not be known until April next year. Delays on this scale influence plans and investment decisions, send the wrong signal to the offshore wind sector as a whole, and call into question Britain’s commitment to acting quickly to reduce emissions.”
The 752km wind farm is predicted to bring millions to the area in investment, as well as droves of new jobs.
Julia Nix, district manager for the Department for Work and Pensions for the East Anglia region has written to the planning inspectorate on the matter.
She said: “The consideration of extending it now, so close to the end of the process, when all issues have been examined robustly would potentially give the wrong message both locally and nationally.
“The level of uncertainty this would cause would almost definitely have a negative impact on investor confidence and the region’s socio-economic economic strategy.”
Chris Starkie, chief executive of the New Anglia LEP, and Nova Fairbank, head of policy, governance and public affairs at the Norfolk Chambers of Commerce have also written to the secretary of state asking for the process not to be delayed.