Former prime minister Tony Abbott has backed a call from same-sex marriage opponents to ban American rapper Macklemore from performing his pro-gay song Same Love at the NRL grand final.

Former player Tony Wall, who played first grade briefly in the mid 1990s, is petitioning NRL boss Todd Greenberg to halt the half-time performance and "take a neutral position on the question of same-sex marriage".

The Coalition for Marriage, the official "no" campaign vehicle, seized on the Change.org petition on Wednesday, demanding the NRL ban the song despite making "freedom of speech" one of its central campaign tenets.

Spokesman David Goodwin said the grand final was "not a PC lecture theatre" and it was "bizarre that the NRL would choose to use its half-time entertainment to push a message which it knows millions of Australians disagree with".