Pizza Hut has apologised after one of its Melbourne stores offered customers "one free small animal" if they bought 10 large pizzas.

The deal, offered by Pizza Hut in Mt Waverley, in conjunction with a local pet store, was dumped after outcry from animal rights activists.

It also sparked outrage on social media, with animal welfare group Oscar's Law encouraging people to voice their opposition to the promotion on the fast-food chain's Facebook page.

Angry users slammed the offer as "disgusting", "irresponsible" and disgraceful", and some threatened to boycott the pizza chain.

"Please stop promoting your pizza for a small animal deal! It's so wrong on so many reasons!" Kellie Rose wrote.

"Absolutely disgraceful promotion Pizza Hut!! I will never order from you again!!" Deanne Brent wrote.

After the torrent of negative posts, Pizza Hut issued a statement saying it had not approved the deal and the store's owners had agreed to stop the promotion.

The statement read: "We would like to sincerely apologise to anyone who was offended by this.

"The poster has since been taken down and all those involved have been made aware of the severity and inappropriateness of the promotion.

"We would like to thank Oscar's Law and all those who have brought this to our attention this evening.

"On behalf of Pizza Hut Australia we once again apologise for this thoughtless promotion ever occurring and would like to reassure you all that this matter is being seriously dealt with."