Controversial cartoon series South Park has enraged Catholic groups after producing an episode featuring a bleeding statue of the Virgin Mary.

Church leaders in New Zealand are urging Catholics to boycott national television network C4, who intend to screen the "ugly and tasteless" episode on the 22 February (06).

Prime Minister Helen Clark admitted she had not seen the show but said it sounded "revolting", and warned the network they should reconsider the consequences of broadcasting the programme.

A letter signed by Catholic bishops asked the country's 500,000 Catholics to boycott C4 and its sister station TV3, which recently apologised for showing the Danish cartoons of the Prophet Muhammad.

The letter read, "Making known the extent of our offence might give them pause to consider that press freedom is not a licence to incite intolerance or to promote hated or derision based on religion, race or gender."

Rick Friesen, head of TV Works, which runs C4, responded that Catholics who feel offended by the storyline should not watch the show.