A row between Catholics and media firm CanWest has escalated with the controversial "Bloody Mary" episode of South Park screening on television tonight, weeks ahead of schedule.

The Catholic Church says the move is "provocative and inflammatory".

At least one advertiser has pulled its advertising from CanWest's radio stations. The move by CanWest to screen the episode seven weeks early follows an open letter from seven bishops on Sunday urging Catholics to boycott TV3's news and advertisers should the company go ahead with the screening on its sister channel, C4.

The church's communications director, Lyndsay Freer, said she was handed a press release at 5pm yesterday announcing the decision to run the episode today, and was asked to comment for the 6pm news.

Being ambushed with the release and asked for immediate comment was cynical. "It was an incredibly arrogant, unethical and inflammatory thing to do."

Mrs Freer will lodge a complaint with the Broadcasting Standards Authority about TV3 "setting her up".

She said the South Park episode, which shows a statue of the Virgin Mary spurting blood at the Pope, is offensive to Catholics, people of other faiths and women in general.

"CanWest justifies screening the episode by calling it satirical comment. What point is made by associating the Virgin Mary with rectal and menstrual bleeding which hits a cardinal and, I think, the Pope, in the face?"

Mrs Freer branded the move "provocative and inflammatory".

"While we think that freedom of the press is absolute in one sense, whether it's satire or not, it's still governed by broadcasting standards.

"Whatever the genre, there are still standards of decency and good taste."

Patrick Quin, owner of the recruitment agency Max Recruitment, said he had withdrawn advertising worth about $6500 a month excluding GST from CanWest in protest at the decision to broadcast the episode.

"I just think it's grubby," said Mr Quin, who described himself as a non-practising Catholic.

He said a CanWest manager phoned him yesterday to discuss his move and told him that not many other advertisers had pulled their ads.

CanWest said it was bringing the episode forward to 9.30 tonight in response to high levels of debate.

South Park usually draws about 30,000 viewers.

"Given that by far the majority of those involved in the debate have not had the opportunity to view the episode, we feel it is important to give the public of New Zealand that chance," said Rick Friesen, chief operating officer of CanWest-owned TVWorks.