The Australian Security Leaders Climate Group says the findings are particularly important as the nation debates defence priorities, submarines and the impact of China in the region.
The group includes former Defence Force chief Admiral Chris Barrie and former Defence director of preparedness and mobilisation Cheryl Durrant.
"With the federal government now leading a national debate on the nation's defence priorities and their response to potential threats within our region, the Australian public deserve to know the full range of security threats our nation faces - particularly those posed by worsening climate change," Admiral Barrie said.
Last month, Prime Minister Anthony Albanese revealed new details about a $368 billion deal to acquire nuclear-powered submarines under the AUKUS security pact.
From as early as 2027, boats from the United States and United Kingdom will begin rotating through Western Australia as part of the agreement.
Admiral Barrie said the Australian government had been transparent about other threats to Australia including cyber security and the COVID-19 pandemic, so climate change should be no different.
In mid-2022, Australia told the United Nations it would order a risk assessment of the implications of climate change.
The security leaders group believes the Office of National Intelligence likely completed that assessment and handed over the findings to government in November 2022.
It requested a declassified copy be released in February this year, but did not receive a response.
"Both the United Nations and the US secretary of defence have described climate disruption as an 'existential' security risk, however climate security risks are missing in action in our current defence debate, led by politicians and the media," Admiral Barrie said.
"In defending the rights of all Australians, a government has no greater duty than to fully assess all the risks to security and be frank with the electorate about the threats we face as a nation and how to respond."
A spokesperson for the Department of the Prime Minister and Cabinet declined to comment on whether the classified information-based report would be released publicly.
