Anti-horse racing protesters are cracking their whip outside Auckland's annual Spring Race Day.

They're beginning to line the entrance to Ellerslie Racecourse with placards and banners opposing alleged animal cruelty within the racing industry.

Coalition for the Protection of Racehorses spokesperson Aya Oba says they're urging punters to think twice and reconsider their support for the sport.

She says the horses often experience several and heart attacks because they're pushed to their limits.

The group also hopes to bring attention to the issue of live exportation.