DUP Environment Minister Arlene Foster has insisted she considered proposals for a commercial Giant's Causeway visitor centre totally unaware that the prospective developer had enjoyed support from her party leader and his MLA son.
In a forceful interview with the Belfast Telegraph, Mrs Foster also indicated that a final decision on the Causeway application by property tycoon Seymour Sweeney is still months away.
But she was today urged to "distance herself" from the ongoing row by calling a public planning inquiry.
Alliance leader and Assembly Environment Committee member, David Ford, claimed an independent inquiry is the only way to ensure an "acceptable decision".
Mrs Foster announced last month that she was "of a mind" to grant Mr Sweeney approval for a new Causeway centre development.
The issue has since been embroiled in controversy over past lobbying in support of the businessman by DUP leader Ian Paisley and Assemblyman Ian Paisley Jnr.
In her first detailed newspaper interview on the row, Mrs Foster asked: " Why would I know what a constituency's MP and MLAs were pushing for?
"I wouldn't have a clue, for example, what other MPs and MLAs are pushing for in other areas."
She also stated: "There was no reason before May why Ian Jnr or Dr Paisley, or indeed anybody else would have spoken to me about this issue.
"Since then, I have not had any meetings with Dr Paisley and Ian Jnr and I was not aware that they were supporting Seymour Sweeney in his application."
Mr Ford today disclosed that he has written to the Minister asking for a planning inquiry.
"Without in any way suggesting she has behaved improperly, I believe that her provisional opinion is deeply flawed," he said.
"Given all the issues surrounding her party colleagues, it is also difficult to see how the Minister's decision will be accepted across the range of interested parties.
"I believe that she now has to distance herself from the controversy if this matter is to be resolved satisfactorily."
Mr Ford said the Minister had the option of referring the application to the independent Planning Appeals Commission (PAC) for a public inquiry.
He added: "If she were to announce that she would accept without amendment whatever decision was recommended by the PAC, she could distance herself from the controversy and defuse the party political debate around the issue."
DUP Minister Edwin Poots has claimed a "vendetta" is being waged against Dr Paisley and Ian Paisley Jnr on the Causeway centre.
Mr Poots told Radio Ulster's Talkback show yesterday: "I'm deeply concerned that some people who are operating in terms of investigative journalism would appear to be operating on the basis of a vendetta."
The DUP has meanwhile distanced itself from speculation that the visitor centre issue was raised during last year's St Andrews talks on the restoration of the Assembly.
In a statement, it said any representations would have been made on the margins in an "individual capacity" without the party's " knowledge or consent".