The chairman of the Wales Film Agency has said it is time for the consortium behind plans for a "Valleywood" film studio to "put up or shut up".
Peter Edwards said there had always been uncertainty over the project
An announcement on the plans for the £330m film studio near Bridgend is said to be expected within a few weeks.
Six years since the project was revealed, Peter Edwards said people needed to know what was happening.
The company behind the plans, Dragon International Studios, said it could not comment.
"The worry that it might not happen has always been there," Mr Edwards told BBC Wales' Dragon's Eye TV programme.
"It's to do with the dollar-pound ratio and how much business will come out of Pinewood and the other London studios.
"We need to know what's happening... it would be great to have it but you just feel for us to plan for the future they should put up or shut up".
Lord Attenborough has been closely involved with the project
Progress on the complex at Llanilid has been halted amid problems over sewerage plans, and bad weather.
Ogmore AM Janice Gregory has written to Economy Minister Brian Gibbons, expressing her worries and said little had happened on the former opencast site.
"They are becoming more vague as to when the contractor will be appointed and where they see themselves in six months," she said.
Construction work had previously been held up for months while investigations ensured the development would not harm any of the dormouse population.
"They blamed the rain, they blamed the fact they were building on a former open cast site, the dormice and the bats," Ms Gregory added.
"We've understood all the difficulties but I think now is the time for them to be clearer as to what their intentions are."
But Rhondda Cynon Taf Council said it had been working closely with Dragon International.
The 12-studio complex will offer filmmakers a new location
Councillor Robert Bevan said work would start on the site "very much in the near future" after "major planning issues".
Oscar-winning actor and director Richard Attenborough, who has been the project chairman, said in January 2006 it would "build studios that have not been seen for decades throughout the world".
Organisers have said the 12 state-of-the art sound stages and TV studios will make south Wales a centre of the UK film industry.
The Valleywood complex aims to bring 12 studios, including one of 30,000 sq ft and two of 20,000 sq ft to provide facilities for recording anything from a quiz show to a big screen blockbuster.
Developers say the project will create 1,700 jobs initially and thousands more later.