A defence filed by broadcaster Alan Jones in his defamation battle with former NSW deputy premier Andrew Stoner contains "scandalous" and "irrelevant" material and should be kept confidential, the Supreme Court has heard.

Mr Stoner, who was leader of the NSW Nationals until he quit in October, has sued Mr Jones and Greens MP Jeremy Buckingham over a series of broadcasts on radio 2GB in June and August last year.

Broadcaster Alan Jones: allegations of defamation. Credit:Alex Ellinghausen

Mr Stoner's barrister, Terence Tobin, QC, told the court on Friday that parts of the defence filed by Mr Jones and Mr Buckingham should be struck out or kept confidential under a court rule dealing with material which is "scandalous, frivolous, vexatious, irrelevant or oppressive".

Justice Lucy McCallum will decide next week whether the material should be kept secret.