The large poster depicts a dejected-looking Joseph lying next to Mary, whose eyes are turned heavenwards, under the words: “Poor Joseph. God was a hard act to follow.”
Both figures, painted in classical fresco style, appear to be naked.
Within hours of the billboard being erected outside the Anglican church of St Matthew’s in the City, in central Auckland, it had been attacked by a man who clambered on to the roof of his car to smear brown paint over it.
As a result it was almost obliterated and the church, which describes itself as “progressive”, is seeking a replacement.
Archdeacon Glynn Cardy said the billboard was intended to lampoon the literal interpretation of the Christmas conception story “and that somehow this male God impregnated Mary”.
“What we’re trying to do is to get people to think more about what Christmas is all about,” he said.
“We actually think God is about the power of love as shown in Jesus, which is something quite different than a literal man up in the sky.”
He said the church had asked an advertising agency to come up with ideas for the poster and the one they had chosen was not the most radical.
“One of the options we turned down had a sperm coming down with the words ‘Joy to the World’,” he said.
St Matthew’s was inundated with angry phone calls and emails soon after the billboard appeared at a busy street corner on Thursday.
The poster also sparked a barrage of comments to radio stations and on internet websites.
Among leading critics was Lyndsay Freer, a spokesman for the Catholic Church, who said: "This is disrespectful and offensive to all Christians.
“It’s flying in the face of our 2,000-year-old beliefs,” she said.