Folau's future in rugby is again in doubt after the code-hopper took to Twitter to proclaim hell awaits "drunks, homosexuals, adulterers, liars, fornicators, thieves, atheists and idolaters".

It's his second such outburst in as many years and Rugby Australia's integrity unit is "engaged on the matter".

Kerr used Instagram to write comments over a screenshot of Folau's image.

She labelled Folau's post "embarrassing".

"Australia, we should not let athletes or ANYONE preach this hate in our country

"You must be proud @wallabies @nswwaratahs".

Welsh rugby great Gareth Thomas and former England back-rower James Haskell also responded to Folau's divisive views.

With 100 Test appearances Thomas came out as gay in 2009 and was the victim of a homophobic attack in Cardiff late last year.

The incident prompted the All Blacks as well as the French, Welsh and English national teams to don rainbow coloured laces during Tests.

The former British and Irish Lion said he felt sorry for Folau.

"I don't write this with hate or anger after Israel Folau's comments. I write with sympathy," the 44-year-old tweeted.

"To everyone who reads it, don't be influenced by his words. Be the better person and be YOU. Whoever YOU is..Hell doesn't await YOU.Happiness awaits YOU."

Thomas's message was replied to by All Black Nehe Milner-Skudder with a rainbow and love heart to show his support.

Haskell was more critical of Folau.

"This is the biggest load of shit I have ever read. Sport has no place for this crap. Keep it to hate groups @IzzyFolau , you arent spreading the lords word. You are spreading hate.

"You are an unreal player, but a f**king misinformed bigot," Haskell tweeted.

Retired England prop Joe Marler simply responded with an image of two men kissing.

International Gay Rugby, the global organisation for the gay and inclusive rugby clubs, also hit out at the 30-year-old.

"The effects these hateful comments will have on LGBT people are enormously harmful," it said:

"We want all LGBT athletes out there to know that rugby is a sport where you are welcome and respected, a sport of values that doesn't allow for such bigotry or discrimination of any kind."

Folau did have some public support in One Nation politician Mark Latham, who said the footballer was entitled to his views.

"I stand with Israel Folau in defending his right to free speech, expressing views consistent with his legitimate religious beliefs," Latham tweeted.

"That a footy player can be hounded by Leftist-PC media this way is a disgrace."

Australian Associated Press