Thorny issues await the two prime ministers when they meet in Australia this week

As gang violence in New Zealand soars – partly fuelled by Australian deportees, police say – prime minister Jacinda Ardern is heading to Sydney for her annual bilateral with Scott Morrison.

The issue of New Zealanders with only distant links to their home country being summarily shipped back to Aotearoa will again be on the agenda, but experts say it is unlikely Ardern will take as tough a stance as last year, when she said the issue was having a “corrosive” affect on trans-Tasman relations.

“We have seen cases where there is also almost no connection of an individual to New Zealand who have been deported,” Ardern said after her bilateral with Morrison last year.

Play Video 0:45 Jacinda Ardern lets phone call from Scott Morrison go to voicemail – video

“I consider that to be a corrosive part of that policy. And it’s having a corrosive effect on our relationship.”

Before her departure on Monday, Ardern reassured New Zealanders she planned to once again tell Morrison the policy “was wrong”, though she ruled out a tit-for-tat by introducing deportations for Australians convicted for serious crimes.

“It continues to be a policy I fiercely disagree with. It’s wrong and I will continue to raise that,” Ardern said.

Other issues likely to be discussed include the coronavirus outbreak, China’s growing influence in the Pacific, terrorism, trade and the climate crisis – a thorny issue for Morrison after a summer of catastrophic bushfires in which he was accused of being a climate denier on the world stage.

Robert Ayson, professor of strategic studies at Victoria university, says Ardern is likely to water down her criticism this year, because she has little in the way of leverage to push more strongly on the issue of deportees.

“I think there is an expectation now that Australia won’t budge very much on this issue, so I don’t think we should expect so many fireworks this time around,” said Ayson.

Ayson said some differences between Australia and New Zealand were more evident under Ardern and Morrison than previous leaders, but the relationship overall remained strong.

“You’ve got governments at the moment on both sides of the Tasman with some different views on things, and the differences are on domestic issues, which makes it a bit more complex,” he says.

Jacinda Ardern says Australia has to 'answer to Pacific' on climate change Read more

“At the moment the relationship is a bit more complicated, but at the same time, the fluidity of international affairs in the Trump era … means that there’s a lot of room to emphasise the common interest between New Zealand and Australia.”

Some political commentators in New Zealand have speculated about whether Ardern – now considered a world leader on the issue – may make a reference or public statement on the climate crisis, following Australia’s summer of bushfire carnage.

Ardern has aligned herself with Pacific leaders who say climate change is threatening their very existence, and has a meeting with Fijian prime minister Frank Bainimarama prior to meeting Morrison on Thursday.

Morrison has repeatedly been called out by Pacific leaders for his lack of action over the climate crisis. “I thought Morrison was a good friend of mine; apparently not,” Bainimarama told the Guardian of the Australian leader’s much-criticised outing at the Pacific Islands Forum in Tuvalu.

“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?”

Ayson said Ardern’s visit was a good chance for Morrison to align himself with a climate change world leader, and last year the pair issued a lengthy statement reiterating their joint commitment to battling the issue, a similar stance they could take again this year.

“It’s hard for New Zealand to say to Australia … you need to change, I don’t think there’s a lot of mileage in that,” Ayson says, adding that New Zealand’s action in the climate arena was significantly less than its talk, which made it vulnerable to criticism.

The deportation battle began when changes to Australian law in 2014 mandated the automatic cancellation of a visa for anyone sentenced to 12 months or more in jail, and in the past five years more than 4,000 people have been stripped of their Australian visas and returned to their country of birth, regardless of how long ago they left. New Zealanders have made up the vast bulk of the deportations.

On Monday, New Zealand’s opposition National party said if elected in September it would move to deport Australians convicted of serious crimes in New Zealand, making the arrangement between the two countries “reciprocal”.

“While Jacinda Ardern has labelled this issue as corrosive to our relationship with Australia, I don’t agree,” opposition leader Simon Bridges said. “In principle, if it’s right for Australia, it’s worth exploring whether it’s also the right position for New Zealand and our interests.”

Ardern rejected Bridges’ suggestion, calling it “naive” and said fixing one wrong with another wrong didn’t make it right. “My view is if we think this policy is wrong, why would we then repeat it?” Ardern said.