Fiji's Prime Minister Sitiveni Rabuka has backed Australia's nuclear submarine plan as Australia conducts a major diplomatic blitz to reassure the region about the landmark AUKUS announcement.

Mr Rabuka met Prime Minister Anthony Albanese during his brief stop in Fiji on his way back from San Diego, where he unveiled the long-awaited details of Australia's pathway to nuclear powered submarines with US President Joe Biden and UK Prime Minister Rishi Sunak.

China has continued to fiercely criticise the plan, while some South-East Asian and the Pacific countries have expressed concerns it might fuel a regional arms race.

But Mr Rabuka told reporters travelling with Mr Albanese in Fiji that he backed AUKUS, and that Mr Albanese had assured him Australia's submarine push would not undermine the Treaty of Rarotonga, which declares that the South Pacific is a nuclear weapons-free zone.

The response from Indonesia – which expressed sharp concerns about Australia's nuclear submarine plan when Scott Morrison made the shock announcement in 2021 – has been relatively cautious and measured this time around.

In a statement, Indonesia's Foreign Ministry said Australia would have to develop a "verification mechanism that is effective, transparent and non-discriminatory" to ensure the nuclear submarine proposal didn't undermine the nuclear non-proliferation treaty.

But the statement didn't directly criticise the announcement or the government, simply saying that all countries in the region had a responsibility to maintain "stability" in South-East Asia.

Malaysia's Foreign Ministry issued a more pointed statement, which included a thinly veiled criticism of AUKUS, warning against "provocations" which "could potentially trigger an arms race in the region".

Malaysia's suspicion towards AUKUS has in the past frustrated Australian officials, who have privately pointed out that the South-East Asian nation has not complained about the way China has built up a massive military force in recent decades – including 12 nuclear powered submarines.

Australia, Indonesia share vision for the region

Foreign Minister Penny Wong said the government had poured significant time and effort into explaining the government's rationale for obtaining nuclear powered submarines, and stressed that the boats would not be armed with nuclear weapons.

"Obviously we've engaged very closely with our region in the lead up to this and made sure they weren't blindsided in the way they were under the Morrison government," Senator Wong said.

Senator Wong also said Australia and Indonesia shared the same vision for the region.

"I would just make this point that the Indonesian Foreign Ministry official statement made the same statement I made to you this morning — that maintaining peace and stability in the region is the responsibility of all countries" she said.

Wong to address Pacific nuclear concerns

The government has waged a widescale diplomatic push both before and since the AUKUS announcement, with senior ministers and officials from the prime minister down briefing their counterparts across Asia, the Pacific and Europe.