Australia is facing a major defence shake-up if China manages to base warships in the Solomon Islands.
Security experts and Australian Defence Force senior commanders flagged an overhaul in military operations after the Solomon Islands initialled a security agreement with China.
The deal opens the way for the superpower to base military forces on the Pacific nation less than 2000 kilometres from Australia's coastline.
Defence analyst Malcolm Davis said if Chinese naval forces are based in the Solomon Islands, Australia will have to respond with a "fundamental change" in its military operations.
It would involve switching the focus from the traditional "sea-air gap" to the north and north-west of Australia, Davis, of the Australian Strategic Policy Institute, said.
"We now have to think more about defending the east coast ... there will likely be more focus on better surveillance by naval, space and air assets to monitor Chinese activities," he said.
From an advance military base in the Solomon Islands capital Honiara, China would be better able to exert influence on other Pacific island states.
Davis said after the May Australian general election, the incoming government should review military capabilities on the eastern seaboard to keep pace with the changing security environment.
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And a top Australian Defence Force (ADF) commander said an increased Chinese presence in the Pacific would mean an overhaul of day-to-day operations.
Lieutenant-General Greg Bilton, ADF Chief of Joint Operations, was speaking during a visit to the Australian Signals Directorate in Canberra on Thursday.
"It does change the calculus if Chinese navy vessels are operating from the Solomon Islands," General Bilton said.
He said if Chinese forces are based there, ADF operations would have to adapt to new security challenges.
"They're in much closer proximity to the Australian mainland, obviously, and that would change the way that we would undertake day-to-day operations particularly in the air and at sea.
"We would change our patrolling patterns and our maritime awareness activities."
Diplomatic snub for Australia
After details of the deal were finalised by officials yesterday, Solomon Islands Foreign Minister Jeremiah Manele and his Chinese counterpart Wang Yi will now formally sign the agreement.
Signing the deal will be a rejection of pressure by the Australian and New Zealand governments who opposed it.
The Solomon Islands government said in a statement that officials have "initialled elements of a bilateral security cooperation framework" with Beijing.
It added the Pacific nation would continue to work with all partners including Australia "in providing a safe and secure nation where all people are able to co-exist peacefully".
Under the draft agreement, leaked last week on social media, Chinese naval ships and other military forces will be permitted to be based in the Solomon Islands to protect Chinese projects and citizens there.
The Pacific nation's closer relations with China come after rioting erupted in the capital Honiara last November.
Australia and other neighbouring countries sent police and military personnel there to restore order.