A councillor has “hours” of recorded conversations with officials connected to a legal challenge over a planned £20m hotel and leisure complex on the north coast.
Padraig McShane told the High Court he used an electronic device to tape the encounters.
Causeway Coast and Glens Borough Council is now seeking an order for him to hand over any recordings.
A judge is expected to rule on its application for disclosure next week.
The intervention by Mr McShane has already led to the challenge mounted by TUV leader Jim Allister being put on hold.
Mr Allister is judicially reviewing the council for giving the green light to the accommodation in Portstewart.
Mr McShane was a member of its planning committee who approved the proposed resort earlier this year.
Plans include a 120-bedroom hotel, spa, holiday cottages and restaurant.
But the case was adjourned earlier this week when it emerged that the independent councillor has sent a sworn affidavit to both the attorney general and the Northern Ireland Public Services Ombudsman setting out his claims.
At a further hearing on Friday he was granted interested party status and asked about the alleged recordings.
He told Mr Justice McCloskey that he has “hours” of material taped on a device other than a mobile phone.
A barrister representing the council confirmed the extent of disclosure being sought.
Stewart Beattie QC said: “We are seeking any recordings or documentation that is relevant to those proceedings.
“At this stage the correspondence makes a series of assertions that may have wider-reaching consequences, we don’t know.”
With no lawyer present to represent Mr McShane, the judge adjourned the disclosure application to next week.
Permission for the hotel and leisure complex was first given in June 2017, but withdrawn after Mr Allister initially threatened legal action.
The North Antrim MLA, who has a home overlooking the development site, is seeking a judicial review along with another local resident.