The Sam Group is a Chinese conglomerate and describes itself as a strategic partner of the state-owned China National Chemical Corporation.

The deal was inked just days after the Solomon Islands abandoned Taiwan and began diplomatically recognising China, paving the way for Chinese aid and investment to flow.

Solomons Island Prime Minister Manasseh Sogavare was given a red carpet reception in Beijing last week when he met President Xi Jinping and agreed to sign up to the Belt and Road Initiative.

News of the lease agreement sent Australian diplomats scrambling to find out more details.

Foreign Minister Marise Payne and Pacific Minister Alex Hawke had not responded to a request for comment at the time of going to print.

But in response to suggestions last year China was looking to establish a military base in Vanuatu, former prime minister Malcolm Turnbull said that would be a "great concern".

Australian Strategic Policy Institute executive director Peter Jennings warned the agreement could lead to a Chinese military base being established on Australia's doorstop, particularly if the Solomons Island defaulted on any loans.

"There seems to be a pattern of Chinese state-owned companies leasing a port or airport facilities and doing a bit of development and it's all put in the context of supporting tourism or fisheries," he said.


"The risk is that what is happening is a strategic first jab and the second punch is a dual use or military use port that comes after."

Mr Jennings said the Solomons was in a very strategic location, noting that it was where the Japanese advance was halted in World War II.

He said China was trying to control all approaches to the Asian mainland "and if you do that, you complicate the task of the US to get to Asia".

Mr Jennings said following the Solomon Islands switch from Taiwan to China, there had been a concerted effort in Honiara by Beijing to reduce Australia's influence and try to sign as many deals as possible.

"It's quite a serious step back for the Pacific step up," he said of the lease.

"Our government would be worried by developments in the Solomon Islands. That's not to say they can't be reversed but they're running counter to Australia's interests."

Lowy Institute Pacific Islands program director Jonathan Pryke said Mr Manetiva's comments cast doubt about whether the agreement would go ahead but nonetheless was a jolt for Australia about the need for vigilance to keep China's strategic interests in check.

While low in probability, Mr Pryke said the potentially high cost to Australia was "China will use this investment to set up a military presence in the Pacific and that would change how Australia looks at security in the region".