An attempt by Denis O'Brien to have Galway-based businessman Declan Ganley joined as a co-defendant in Mr O'Brien's action against consulting and PR firm, Red Flag, will be heard next month.

Mr O'Brien believes Mr Ganley is the client who commissioned Red Flag to put together a dossier of material about Mr O'Brien although Mr Ganley has said he is not.

This dossier, which Mr O'Brien says was on a USB memory stick delivered anonymously to his Dublin office in October 2015 is at the centre of Mr O'Brien's action alleging defamation against Red Flag and a number of its executives and staff.

Red Flag denies defamation or conspiracy.

It has alleged there are significant issues concerning how Mr O'Brien got the material. And it argued it was entitled to preserve its client's anonymity.

This morning, Senior Counsel Michael Cush, on behalf of Mr O'Brien, said he wanted to join a co-defendant and amend the statement of claim in the case.

The application is being opposed and the court heard it would take around two hours.

Mr Justice Seamus Noonan said he would hear it on 13 March.