Controversial New Zealand X Factor judges Natalia Kills and Willy Moon have been axed after an on-air tirade at a contestant.

MediaWorks, which owns TV3, says the couple are no longer suitable to judge the reality television show.

The decision follows Kills and Moon's stinging attacks on contestant Joe Irvine during Sunday night's show. After Irvine's performance of Cry Me a River, Kills launched into a stinging critique.

"As an artist who respects creative integrity and intellectual property, I am disgusted at how much you have copied my husband (fellow judge Willy Moon), from the hair to the suit. Do you not have any value or respect for originality?