The party's representatives on Coleraine Council last night joined with other parties to unanimously oppose the controversial plan favoured by DUP Ministers Arlene Foster and Nigel Dodds.

And Coleraine's DUP mayor today suggested that it could take legal action in the absence of a rethink.

Mrs Foster, the Stormont Environment Minister, stated this week that she was minded to give north coast developer Seymour Sweeney planning approval for a visitor complex project at the Causeway.

Mr Dodds responded by pulling the plug on his Department of Enterprise's backing for a publicly funded development - to finally replace the centre destroyed by fire in 2000.

The National Trust, which owns the Causeway stones, voiced dismay at the Ministerial announcements.

Moyle Council, which owns the car park at the famous attraction, is due to discuss the situation on Friday.

Last night's Coleraine vote was proposed by the SDLP's John Dallat, who today described it as a "huge embarrassment" for the DUP's high command.

He also said: "The Giant's Causeway, while not our council area, is our 'pot of gold' in tourism terms."

Coleraine DUP mayor, Maurice Bradley, today said legal action could be considered.

"We will wait until we get the response from the DoE minister but until the whole council gets that response we cannot make a decision."

Mr Sweeney has confirmed that he is a DUP member. His links to the party were raised in an Assembly debate yesterday by Sinn Fein, the SDLP and the Alliance.

The Environment Minister said she had been unaware of the developer's affiliation and threatened to sue anyone who impugned her integrity.

Mrs Foster today said the Coleraine Council vote undermined claims of a DUP plot in favour of Mr Sweeney.

"I look at the application on its own right. If DUP councillors don't agree, and I am sure they don't agree with a lot of planning applications, that is a matter for them," she said.