Labor has called on the government to provide its advice on why a new national security super-department is needed.
Federal cabinet on Tuesday is expected to discuss an overhaul of national security co-ordination, delivering more responsibility to Immigration Minister Peter Dutton.
Malcolm Turnbull held discussions with British counter-terrorism officials - who operate under the Home Office - in London last week, telling reporters afterwards it was "no time for set and forget" when it came to national security policy.
Labor frontbencher Senator Katy Gallagher says the opposition is prepared to work with the government in the national interest.
But she was staggered to see critical changes to national security "carelessly" leaked to the media ahead of a decision being made.
"Australians would be very concerned if a new national security super department is being created just to keep Peter Dutton happy, especially when it's so vehemently opposed by so many of his colleagues," she says.
"We expect any changes to be based on the recommendations of our security agencies - we want to hear what the experts have to say."
Cabinet has previously rejected the idea of a Home Office or US-style Department of Homeland Security based on advice from experts.
A 2015 review of Australia's counter-terrorism machinery found a super agency "would likely be less, not more, responsive as large agencies tend to be less agile, less adaptable and more inward looking than smaller departments".
The government has received the report of another review, conducted by former senior public servants Michael L'Estrange and Stephen Merchant, but is yet to release its findings.