An Auckland church known for its edgy billboards has come under another attack from vandals.

St Matthew in the City put up a "gay-dar" billboard on Friday, which shows a spectrum from gay to straight, with a cross acting as a gauge.

A message underneath states: "As used by the Anglican Church to assess potential priests."

Church spokesman Clay Nelson said the sign aimed to highlight discrimination in the Anglican Church against members of the gay and lesbian community.

However, it had already been vandalised.

Mr Nelson told NZPA he hoped the billboard could be repaired, and he was looking into that today.

"I'm not sure what the cost will be. We were able to recover the cross and I think it can be mended. So if that's the case, it won't cost too much, hopefully.

"From our history with billboards, we're not surprised when someone decides to debate by vandalism. But that's not going to stop us. We're going to keep at it," Mr Nelson said.

The repaired billboard would stay up for some time, and he was pleased it had attracted attention.

"Hopefully it's got people talking about the issue, which we think is pretty important," he said.

St Matthew's has launched an online petition asking the Anglican Church to stop New Zealand bishops from refusing to consider anyone for ordination who is gay or lesbian and in a committed relationship.

The church is known for its controversial billboards.

Last year, a billboard portraying a sombre Mary and Joseph in bed, with the caption "Poor Joseph. God was a hard act to follow", was repeatedly vandalised.

The church took that billboard down after four attacks.

The Advertising Standards Authority received a number of complaints, saying the billboard was offensive, insensitive, blasphemous, ridiculed the beliefs of Christians, perverse, and distorted children's perceptions of Christmas.

However, it chose not to uphold the complaints, saying the billboard may have been controversial but was not obscene.