Northern Ireland's Environment Minister Arlene Foster is considering legal action against fellow MLA Daithi McKay in the row over the Causeway visitors' centre.
The DUP minister said officials were examining comments made by Mr McKay of Sinn Fein on November 8th.
She has defended her reputation amid sustained criticism of September's announcement that she was minded to grant a private planning application from north Antrim businessman Seymour Sweeney over a public sector alternative.
"I am currently seeking legal advice on the action of his statement of November 8 and in relation to that I am not going to make any further comment," she said.
"I am sure he will be hearing from either me or the departmental solicitor's office in the near future."
The DUP minister's position has been subjected to searching scrutiny from MLAs after it emerged Ian Paisley Jnr worked with constituent and party member Mr Sweeney on the issue in the past.
Ms Foster's threat came after Mr McKay an MLA for North Antrim used parliamentary privilege in the Assembly today to quiz her about the issue.
"Can I ask the minister to confirm today if she will use her department to take legal action against me and if not will she now recognise that the role of departmental legal advisors isn't to take part in political witch hunts against members of this Assembly," he said.
Mr McKay has released minutes of a ministerial meeting on the matter in July. It showed Ms Foster agreeing with DUP colleague and Enterprise Minister Nigel Dodds that a private development would be the ideal solution.
The minutes showed she did this before receiving all papers on the private plan. Ms Foster has said no final decision has been made.
The SDLP's Declan O'Loan, also from the North Antrim constituency in which the centre is due to be built, was also subject to a broadside from the minister after he asked her what about delays in a Planning Service response.
She insisted planners had nothing to hide. "A new story runs every week when in fact there's nothing new in the story," she told the Assembly.
"It would do well for Mr O'Loan, and indeed other members of this house, to concentrate on getting planning applications through, of whatever nature, for the visitors' centre," she said.
PA