MLA Robin Newton mounted a party defence as Environment Minister Arlene Foster and Enterprise Minister Nigel Dodds continued to take flak for indicating they were ready to go with a private developer for the site – after waiting for seven years for a public funding proposal to emerge.
The DUP Assembly Enterprise Committee member said: "The development of a world-class visitors' centre at the Giant's Causeway is vital for Northern Ireland plc.
"Northern Ireland is blessed with having a World Heritage Site located on the north coast, yet it is mind-boggling that the hundreds of thousands of visitors to this site are being serviced by a wooden hut.
"The DUP argued for devolution because we wanted to make Northern Ireland a success and a world leader in every aspect.
"As part of this strategy, the DUP is about the business of ensuring that tourists to our shores have an experience which is second to none.
"It is welcome that our local ministers are pushing ahead to ensure that this world-class site has a world-class visitors' centre."
But Ulster Unionist MEP Jim Nicholson and others will not let the matter drop – as arguments rage over whether or not the centre should be put in private hands.
Mr Nicholson has written to both DUP ministers, under the terms of the Freedom of Information Act 2000, requesting information surrounding their recent announcements on the centre.
He has specifically requested that the Department of the Environment provide him with all documentation surrounding the minster's decision to be "of a mind to approve" Seaport Investment's planning proposal for a visitors' centre – including the Planning Service's advice to the minister on Seaport Investment's proposal and copies of any correspondence the two ministers may have had on the issue.
Seaport's owner is Seymour Sweeney, a member of the DUP.
Ms Foster and Mr Dodds have flatly denied that having been an issue and warned they will take legal action against anyone who suggests it was.
SDLP East Londonderry MLA John Dallat has, meanwhile, called on the Northern Ireland Tourist Board to clarify its preferred position on the site.
The Ulster Society for the Protection of the Countryside has also requested Ms Foster to reconsider her suggested support for a commercial development at the Giant's Causeway.
"This World Heritage Site is primarily an outstanding geological curiosity and requires a first-class interpretative centre to satisfy the requirements of the many thousands of visitors who travel to the Causeway Coast each year," a spokesman said.
"The Giant's Causeway is not to be seen as an opportunity for commercial gain or profit."
North Antrim Sinn Fein MLA Daithí McKay said the site's World Heritage status could be put under threat by commercialisation.