Vanuatu Prime Minister, Ishmael Kalsakau, says Pacific security is about the security of the Pacific peoples and their way of life as identified by Forum Leaders in the Boe Declaration.
Kalsakau said this reaffirms climate change as the single greatest threat to regional security.
The PM was speaking at the opening of the Pacific Fusion headquarters in Port Vila on Tuesday, alongside Australian Deputy Prime Minister, Richard Marles.
He said Vanuatu, with the world's first climate change refugees with the relocation in 2005 of 100 villagers in Torba Province, "will always consider climate change its top priority".
He said climate change is real, an existential threat, impinging on the security and stability of all nations.
"We do not have to look too far to see how the increased intensity of climate change-induced tropical cyclones wreak havoc on the daily lives and livelihoods of our people and set us back years in our development," said Kalsakau.
He said Vanuatu's Pacific brothers also face human security challenges caused by the nuclear testing in the Marshall Islands, Muroroa and Australia.
"With the effects of global warming and nuclear testing, our ocean is getting warmer, our reefs are dying and fishes are now very scarce.
"Our children and grandchildren are bound to never experience what we've enjoyed in our childhood.
"The maintenance and sustenance of our marine resources must be the top priority of our Pacific Leaders."
Kalsakau said there are other pressing issues such as the Fukushima nuclear waste water discharge and AUKUS.
"I say again that Pacific security is about the security of our Pacific peoples and way of life.
"This is why Vanuatu stood alongside our Pacific brothers and sisters to produce the Rarotonga Treaty. Which brings me to today's very special occasion.
"The Pacific Fusion Centre is guided by the regional security priorities identified by the Boe Declaration and supports regional decision-making on these shared security priorities," he said.
The Centre, which is funded by Australia and to be run in collaboration with Pacific Forum member states, will aim to provide training and analysis on regional security issues.