National is warning Winston Peters they have got buckets of mud to throw, if the New Zealand First Leader continues his personal attacks on them.

The relationship between Mr Peters and National MPs has hit rock bottom after a bout of mudslinging in parliament this week.

National MP Maurice Williamson says he has had enough of Mr Peters trying to make out he is the only decent and honest man in parliament.

He says if the Foreign Affairs Minister wants to get on and do the real stuff, that is fine, but if Mr Peters wants to carry on throwing muck he has got plenty to throw back.