Australia's former Deputy Prime Minister Barnaby Joyce (Michael Masters/Getty Images)

Australia’s Minister for Agriculture Barnaby Joyce has claimed that legalising same-sex marriage would damage relationships with Asian countries.

Prime Minister Tony Abbott is a staunch opponent of equal marriage, but is facing pressure to allow his MPs a free vote on a cross-party marriage bill, following progress in Ireland and the United States.

Ahead of a bill that is set to come to a vote in August, Joyce has warned that allowing gay people legal equality could lead to “judgement” from trade partners in Asia.

He claimed: “Where we live economically is South Easy Asia.

I think that what we have to understand is that when we go there, there are judgments, whether you like it or not, that are made about us.

They see in how we negotiate with them whether they see us as – whether they see us as decadent. That is how they [see it]”

Asked if he meant Asian countries see same-sex marriage as decadent, he said:”I think in some instances they would, yes.”

Barnaby Joyce is best known outside Australia for threatening to have Johnny Depp’s dogs euthanised, after the actor illegally brought them into the country.

Senator Eric Abetz had also warned against equality – as no Asian country has introduced same-sex marriage.

Rodney Croome of Australian Marriage Equality said: “Several of our Asian neighbors allow polygamy and criminalise homosexuality, things most Australians find abhorrent.

“The only relevant international benchmark are those countries closest to us in law, history, culture and language – countries like New Zealand, Canada, the UK, the US and Ireland – all of which have marriage equality.

“Australians will not be guided by what some Chinese or Burmese official thinks is ‘decadent’.”