The Commercial Court has been told that the very existence of a challenge taken by developer Paddy McKillen and his companies against the National Assets Management Agency poses a very real threat to the vital work of the Agency.

Lawyers for NAMA and the State asked the Court to fast-track a hearing of the challenge.

Mr Justice Peter Kelly set a trial date of 12 October.

Mr McKillen is challenging the transfer of €80m in loans his companies borrowed from Bank of Ireland to NAMA.

He said the loans are fully performing and the transfer would have a drastic and detrimental impact on his business and property rights.

He is also seeking a declaration that parts of the act under which NAMA operates are unconstitutional.

Senior Counsel Michael Cush for Mr McKillen said he did not see the proceedings as a full frontal attack on NAMA.

He said the action was in part related to procedures and definitions, but it was hugely important to Mr McKillen.

Senior Counsel Brian Murray for NAMA and the State said part of the challenge alleged that the definition of eligible assets used in the act was unconstitutional.

He said if that part of the act was struck down, it would have very significant implications for NAMA's operations.

In a document sworn in on behalf of NAMA, the court was told that if there was a perception that the system under which NAMA operated was flawed, that would undermine building of confidence in the international markets, which the ongoing work of NAMA seeks to foster.

Mr Justice Kelly said he was satisfied the case was one of very considerable urgency.