The singer who was fired as a guest judge from TV talent show X Factor New Zealand for picking on a contestant has fired back at her critics, accusing them of bullying her.

Natalia Kills has defended her scathing critique of Joe Irvine, insisting she and her husband, Willy Moon, were encouraged to attack wannabes on the show.

The couple was asked to leave the program after poking fun at Irvine's look, which resembled that of Moon's, and Kills tells the New Zealand Herald she has become a victim of online bullies ever since,

She says, "It's so sad how (producers) encourage so much drama but then when their sponsor and the public react badly they release a statement branding us as bullies.

"The racism, homophobia, death and rape threats and online attacks have been a real eye-opener to what bullying really is... It's not the same as criticism. It's not the same as being told off for your outfit choice. It's far greater and sadder than anything I've ever witnessed and I refuse to be the victim of it.

"When Joe hinted at what his show was going to be like I just knew, you know...? But, coming from a music background, my husband and I had no idea how reality TV was set up."

X Factor contestant Irvine has since been eliminated from the competition show.