Labour MP Andrew Little has accused Justice Minister Judith Collins of bullying and intimidation and challenged her to send "thuggish guys" to serve him with defamation papers.
Ms Collins threatened to sue Mr Little, Mr Mallard and Radio New Zealand in March over an interview which linked her to the leak of a sensitive email from former National Party president Michelle Boag.
The High Court yesterday confirmed Ms Collins has launched defamation action against Mr Little and Mr Mallard - though no action has been lodged against Radio New Zealand.
Both Labour MPs remain defiant, saying the case is unlikely to make it into the courthouse.
They are refusing to cooperate with legal requests to allow court papers to be served to them.