Zoocheck Canada, a former Marineland animal trainer, and Ric O'Barry, the star of an award-winning documentary on dolphin abuse, are holding a news conference Friday at the legislature.
Former Marineland employees have alleged animals at the park aren't properly cared for and have delivered a petition with 77,000 signatures calling for stronger rules.
Community Safety Minister Madeleine Meilleur says her staff are currently reviewing the law and will amend it if necessary.
The Ontario Society for the Prevention of Cruelty to Animals says any animal that's under the care of a licensed veterinarian is exempt under the law and can't be investigated.
But Meilleur says that's not a loophole, because vets are obligated to report any mistreatment under the law.
She says they're also required to report mistreatment under their professional code of conduct and can face penalties if they fail to do so.
But if there is a loophole, the minister says she wants to close it.
The Canadian Association of Zoos and Aquariums recently said it found no major issues at the park.
The OSPCA is continuing its investigation of Marineland and says it has identified "some areas of concern."