The run-up to the 2012 Olympics in London could cost the East of England's economy £544m, a new report has found.
The eastern region could benefit from the London Olympics
The economic impact report says the eastern region could lose funds through businesses relocating and competition for labour driving up wage rates.
But the report to the East of England Regional Assembly (EERA) adds that early action could generate £600m for the region as the Olympics approaches.
The Olympics could be used to help boost tourism in the East, it says.
Construction, technology and transport firms in the region will be well-placed to benefit from contracts involved in the 2012 Olympics, says the report.
Councillor Chris White, of EERA, said a business plan had been developed to ensure the region was ready for the Olympics.
He said EERA and the East of England Development Agency (EEDA) were advising firms on the opportunities available.
EERA is made up of representatives of councils in Bedfordshire, Cambridgeshire, Essex, Hertfordshire, Norfolk and Suffolk.