Futerra co-founder Solitaire Townsend is urging clients in the environmental space to pare down their messaging for the next three to six months.
Townsend said: 'The Government does not yet have a clear vision of what needs to be done, or a vision of a better, greener Britain.'
Liberal Democrat Chris Huhne has been appointed Energy Secretary, while Conservative Caroline Spelman is Environment Secretary.
The two will be hammering out agreements on environmental issues, but no agreement had been reached on nuclear power at the time of PRWeek going to press.
Townsend warned campaign groups that confusion was 'kryptonite' to the environmental movement and that they must not add to this by over-complicating their comms strategies.
'We have to pare down our message and stick to that,' said Townsend. 'We're going to have to hold the line on clarity. I'd recommend everyone to be clear on what their call to action is and to keep pumping that out for the next three to six months.'
Townsend added environmental charities would have to get to know many people in Government very quickly - 'and not necessarily the people they were expecting,' she said.
Futerra has represented organisations such as The Carbon Trust, Greenpeace and Defra.