The billboard is one of three paid for by an Islamic group called MyPeace and features a phone number for people to call to receive a free Koran and other Islamic literature.
The organiser of MyPeace, Diaa Mohamed, said the vandalism of the billboard at Victoria Road, Rozelle, ''validates the reason they went up in the first place''.
Read more in the Sydney Morning Herald.
Response to the billboards, which will be followed by bus-side and other advertising, has been mixed. Anglican Bishop of South Sydney, Rob Forsyth, said that while the claims on the billboard were nonsense, the signs were not offensive.