An Australian senator has resigned from the opposition’s frontbench after he said that allowing same-sex couples to marry could lead to sanctioning polygamy and even bestiality.

Cory Bernardi made the comments shortly before the country’s parliament overwhelmingly voted against a marriage equality bill.

During the upper house debate on Tuesday night, Senator Bernardi queried the next step if same-sex marriage was legalised.

“Is having three people that love each other should [they] be able to enter into a permanent union endorsed by society, or four people?” he told the chamber.

“There are even some creepy people out there, who say that it’s ok to have consensual sexual relations between humans and animals. Will that be a future step?”

According to Sky News Australia, Liberal Party leader Tony Abbott announced on Wednesday he had accepted his personal parliamentary secretary’s resignation after a “fairly forthright” conversation.

“I’ve known Cory for a long time. He’s a decent bloke with strong opinions,” Mr Abbott told reporters.

“But discipline is critical. Team play is vital. And that’s what Cory has had some problems with. And that’s why I thought it was very important to act quickly and decisively.”

Senator Bernardi later issued a brief statement explaining his decision to step down but he expressed no regret or remorse for his comments.

“I have taken this decision in the interests of the coalition,” he said.

“My focus is now on directing my time and energy to representing the people of South Australia.”