Environment Minister Arlene Foster has identified four potential hurdles facing the Giant's Causeway visitor centre plan tabled by developer Seymour Sweeney.
The Minister last month said she saw "considerable merit" in Mr Sweeney's scheme and was "of a mind" to grant it approval.
The DUP Minister's Department has since written to one of these bodies, Moyle Council, reiterating that "some aspects" of Mr Sweeney's scheme "caused her concern".
The letter set out four areas where Mrs Foster "requires further advice" - the relationship of the developer's blueprint to existing visitor buildings; its relationship to "other developments in the area"; the ability of the developer's scheme to "integrate into the landscape" ; and its impact on the Causeway world heritage site.
The requirements of world heritage body UNESCO for the location are now at the heart of the visitor centre debate.
The DUP is facing ongoing controversy over the fact that its leader Ian Paisley claimed to a public body in 2003 that Mr Sweeney had UNESCO support.
This assertion, in a letter to the Heritage Lottery Fund supporting a grant bid by the businessman, has been strongly denied by UNESCO.
However, Dr Paisley's politician son Ian Paisley Jnr has defended the claim.
He told a BBC interviewer last Friday: "The characterisation that it was supported or approved in a general way, I think, was a fair characterisation, because anyone who knows how UNESCO works knows that they do not have a formal approval route, that it can only be a general approval.
"And I think that that was fair and for it now to be characterised as something stronger than that general note of support, I think, is grossly unfair to Dr Paisley, grossly unfair to me and grossly unfair to the Democratic Unionist Party."
The DUP leader's January 2003 letter to the Heritage Lottery Fund - revealed by the Belfast Telegraph last week - was written after it had turned down a grant application from Mr Sweeney.
The letter, which appears to have been signed on Dr Paisley's behalf by his son, said: "The application as presented has UNESCO approval and, more importantly, it was a multi-million pound scheme which ought to have attracted Heritage Lottery Fund support."
It also stated: "UNESCO saw and approved the plans and they were actually very impressed by the proposal."
UNESCO has denied giving any such backing and has pointed out that it only deals with proposals from Governments, not from private sector developers.
Moyle Council took its land off the market in February 2002 and Mr Sweeney responded by submitting a planning application for a centre on land in his ownership.