A mischievous biblical bedroom billboard was defaced just over five hours after it was erected in downtown Auckland today.

The controversial billboard, erected by St Matthew-in-the-City Church about 11am, shows Joseph looking down dejectedly and Mary looking sad. Underneath is a caption, ''Poor Joseph. God is a hard act to follow.''

It was seen defaced with brown paint about 4.10pm, with both faces and the caption covered.

The church has said it erected the billboard to inspire people to talk about the Christmas story.

However, it has been called offensive and inappropriate by other Christian groups.