Labour MP Andrew Little says he has responded to threats of legal action from ACC Minister Judith Collins, saying he will not be apologising and the issue is a political one.
Ms Collins is planning to take legal action against Mr Little, fellow Labour MP Trevor Mallard and Radio New Zealand over comments about who leaked details of ACC claimant Bronwyn Pullar to the media.
Mr Little says he received a letter from Ms Collins's lawyer last week and has responded, saying he will not be offering to pay her legal costs.
He says it is his job as an opposition MP to hold ministers to account and is confident that he has not defamed Ms Collins.
"I've said I'm not apologising, I'm not paying her legal costs. I remain, as the result of the advice I've had, confident that nothing I have said is defamatory.
"I've pointed out that this is a political issue and we are in the political arena and it's simply not appropriate for a senior Cabinet minister to go around suing MPs."
Mr Mallard has also responded to Ms Collins, saying he will also not be offering an apology or covering her legal costs.
Radio New Zealand says that, as with the first letter from Ms Collins, it has taken legal advice and has responded accordingly.