Key Points:

A group that stabbed about 1000 plastic knives into Family First director Bob McCoskrie's lawn has apologised for the "prank".

The knives were stabbed into Mr McCoskrie's south Auckland property over the weekend and a threatening note was attached to his front door.

Neighbours said they had seen four women dressed in black on his lawn, but thought they were putting candles out.

Mr McCoskrie's family was not at home at the time of the incident.

The group has since posted another note on his door - this time an apology, The Dominion Post reported.

The note said the "prank" was meant to be harmless fun and the group hoped he would see the funny side.

They said they were "truly sorry" if it had offended or scared the family.