SYDNEY, Australia — Australian rugby officials said on Thursday that they intended to terminate the contract of a star player, Israel Folau, after he posted anti-gay comments on social media.

Mr. Folau, 30, a devout Christian who plays rugby union for both the New South Wales Waratahs and Australia’s national team, the Wallabies, posted an image on his Instagram account on Wednesday warning “homosexuals,” “adulterers,” “atheists” and others that “hell awaits you.”

“Whilst Israel is entitled to his religious beliefs, the way in which he has expressed these beliefs is inconsistent with the values of the sport,” Raelene Castle, the chief executive of Rugby Australia, and Andrew Hore, the chief executive of New South Wales Rugby Union, said in a joint statement.

“We want to make it clear that he does not speak for the game with his recent social media posts.”

The statement said both rugby organizations had made “repeated attempts to contact Israel” since Wednesday evening, to which he had not responded.