Donald Trump has taken a swipe at the former Australian prime minister Kevin Rudd, calling him “nasty” and claiming he “won’t be there long” as Australian ambassador to the United States.

But Australian foreign minister Penny Wong says the government would retain Rudd as American ambassador if Trump wins November’s presidential election, backing him as doing “an excellent job” in the position.

Trump, the Republican presidential nominee for , made the comments in an interview with the former British conservative politician Nigel Farage on GB News overnight.

Rudd, before becoming ambassador in March 2023, had been scathing of Trump. In a tweet still available on his X account, Rudd called Trump “The most destructive president in history”.

“He drags America and democracy through the mud. He thrives on fomenting, not healing, division. He abuses Christianity, church and bible to justify violence.” In another tweet, he called Trump “a traitor to the West”.

Asked by Farage about some of those criticisms, Trump at first appeared to not know who Rudd was, before then insulting him several times.

“I don’t know. He won’t be there long if that’s the case,” Trump said, in a clip of a longer interview posted on social media on Wednesday.

“I don’t know much about him. I heard he was a little bit nasty. I hear he’s not the brightest bulb. But I don’t know much about him.

“But if he’s at all hostile, he will not be there long.”

The Department of Foreign Affairs and Trade was contacted for comment. In a response, an Australian government spokesperson responded only: “Kevin Rudd is doing a good job as Australia’s Ambassador to the United States.”

Asked at a press conference on Wednesday whether Australia would retain Rudd as ambassador if Trump became president again, Wong replied: “The answer is yes”.

Speaking more broadly on Trump’s comments, Wong strongly backed Rudd – under whose prime ministership she served as a minister – and his work as ambassador.

“Mr Rudd is a very effective ambassador. He’s recognised … across this parliament, as doing an excellent job in advancing Australia’s interests in the United States. I point you in particular to the phenomenal amount of work being done on Aukus in the period that he been ambassador,” she said.

“He has been active in engaging with members of Congress on both sides of politics and he is a former prime minister, former foreign minister, his experience and skills mean he will be able to work closely with whoever is elected by the American people as the United States president.”

Wong also noted: “Even [opposition leader] Mr Dutton has expressed confidence in Mr Rudd.”

Since becoming ambassador, Rudd has struck a more conciliatory tone, saying both the US and Australia were “robust democracies” and that he had “worked comfortably and seamlessly” with senior Republicans.

“That’s our job as an embassy and that’s my job as ambassador,” Rudd said last August.

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In the interview, Farage also referred to Joe Hockey – the former Liberal treasurer and a recent US ambassador before Rudd – as “quite a good friend of yours, you got on quite well with him” to Trump, and mentioned the Aukus military pact between Australia, the US and United Kingdom. In the clip posted online, the former president also gave no sign of recognition at the mention of Hockey’s name, and did not make comment on Aukus.

Hockey claimed to have, at times, enjoyed a strong relationship with Trump. Hockey has spoken publicly about the pair playing golf together, and was referred to in some media reports as a “Trump whisperer”.

Asked about Trump’s comments on Rudd in a Sky News interview, deputy Liberal leader Sussan Ley said she declined “to comment on US domestic politics”.

“But I do want to say this, Kevin Rudd is our ambassador, so we want him to do well because he represents Australia’s national interest in the US.

“Let’s see what happens in November, let’s see about the next steps in the US and I’m not going to make commentary on what might transpire.”

But Nationals leader David Littleproud claimed Trump’s stance on Rudd meant the Australia-US relationship could be affected.

“It shows that he was a poor choice to start with. And now if we have a Trump administration, that we’re going to have a very difficult time in negotiating with the new administration, particularly with things as important as Aukus,” he told Sky.

“I think this is a problem for the government. They mismanaged this and Kevin Rudd should have known better than to make disparaging comments about a potential future president of the United States.”

• Donald Trump
• Kevin Rudd
• Australian foreign policy
• Australian politics