Scott Morrison has been accused of causing an extraordinary rift between Australia and Pacific countries by the prime minister of Fiji, who said the Australian prime minister’s insulting behaviour while at the Pacific Islands Forum in Tuvalu would push nations closer to China.

In an exclusive interview with Guardian Australia after the conclusion of the PIF, Frank Bainimarama, the prime minister of Fiji and a political heavyweight in the region, said Morrison’s approach during the leaders’ retreat on Thursday was “very insulting and condescending”.

“Yesterday was probably one of the most frustrating days I have ever had,” he said of the leaders’ retreat, which lasted for nearly 12 hours and almost broke down over Australia’s red lines on the climate crisis.

Facebook Twitter Pinterest Frank Bainimarama with New Zealand’s prime minister, Jacinda Ardern, at the forum. Photograph: Mick Tsikas/EPA

“After yesterday’s meeting I gathered [Morrison] was here only to make sure that the Australian policies were upheld by the Pacific island nations,” said Bainimarama.

“I thought Morrison was a good friend of mine; apparently not.

“The prime minister at one stage, because he was apparently [backed] into a corner by the leaders, came up with how much money Australia have been giving to the Pacific. He said: ‘I want that stated. I want that on the record.’ Very insulting.”

Bainimarama said the interaction with Morrison had made him so angry that when he watched rugby union’s Bledisloe Cup match on Saturday, he would be cheering for the All Blacks, despite being “a Wallabies fan from a long way back”.

Asked if Morrison’s approach might cause some Pacific leaders to look to China, which is locked in a battle for influence in the region with Australia, Bainimarama said: “After what we went through with Morrison, nothing can be worse than him.

“China never insults the Pacific. You say it as if there’s a competition between Australia and China. There’s no competition, except to say the Chinese don’t insult us. They don’t go down and tell the world that we’ve given this much money to the Pacific islands. They don’t do that. They’re good people, definitely better than Morrison, I can tell you that.

“The prime minister was very insulting, very condescending, not good for the relationship … They [Australians] keep saying the Chinese are going to take over. Guess why?” said Bainimarama, laughing. “You don’t have to be a high-school graduate to know that.”

Bainimarama said Morrison’s approach to negotiating was heavy-handed, with the Australian prime minister trying to force all the other leaders to sign on to Australia’s views.

Facebook Twitter Pinterest Leaders at the Pacific Islands Forum. Photograph: Mick Tsikas/AAP

Vanuatu’s foreign minister, Ralph Regenvanu, told the Guardian that Australia had several “red lines” during negotiations that it refused to budge on, meaning Pacific leaders had to remove all references to coal, references to limiting warming to less than 1.5C and to setting out a plan for net zero emissions by 2050 from the forum communique and climate change statement that came out of the meeting.

“We had said ‘below 1.5 degrees’,” said Bainimarama, who presided over the UN’s leading climate change body, COP23, in 2017 and is a global leader in the fight against climate change. “That’s what was in our official drafts, but your prime minister didn’t want that because it means the Australians will have to come up with a lot of sacrifices. But we’re supposed to be here for the Pacific islands, not only for Australia.”

Bainimarama also commented on the deputy prime minister Michael McCormack’s comments that Pacific island nations affected by the climate crisis would continue to survive “because many of their workers come here to pick our fruit”, saying they were insulting and disrespectful.

“It’s very insulting, but I get the impression that that’s the sentiment brought across by the prime minister. I could feel it yesterday,” he said.

This year’s PIF was the first one attended by a Fijian prime minister since the country was suspended in 2009 for refusing to call elections.

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Though Fiji was reinstated in 2014, Bainimarama did not attend until this year. He said in 2010 that he would not go while Australia and New Zealand were part of the group because they wielded too much influence, telling the ABC: “I don’t think they should be in the forum. They’re not Pacific islanders.”

Bainimarama gave a speech on Monday, addressing these remarks and saying he had decided to return to the forum because “we are in a new era in which both countries are attempting to re-engage with us in a more respectful and inclusive way”.

But on Friday night he said Morrison’s behaviour had caused him to rethink this.

“My sentiments hold true: Australia and New Zealand should not be in the Pacific Islands Forum,” said Bainimarama, though he added that New Zealand’s prime minister had been far more respectful during the discussions.

“[Jacinda Ardern] was much more compromising. She was really good yesterday. She said the right things about climate change and Morrison did not,” said Bainimarama.