China is buying control in the South Pacific and its growing influence in the region could lead to a takeover of Australia, a former US Navy intelligence commander has warned.

The communist superpower is splashing cash at Australia's island neighbours which agree to switch their diplomatic allegiances from Taiwan to Beijing, a bombshell 60 Minutes investigation found.

All countries China makes diplomatic agreements with must not recognise Taiwan, Beijing demands.

The Solomon Islands, Vanuatu and Kiribati are the latest to switch their allegiance to China as it steps up plans to extend its influence in the region.

Former intelligence chief of the US Navy's Pacific Fleet Captain Jim Fanell described China's plans for the South Pacific as a 'soft invasion' and 'expansionist'.

General Sam Kaouna (pictured with wife Josie) has no problems with doing business with China if he becomes Bougainville's first president

'They're interested in this area because it's essentially the lifeline or the choke point between America and Australia and New Zealand,' he said.

'China has built the navy that people said they were never going to build. China has deployed their fleet to places they said they were never going to deploy and they're sending their fleets around the world.

'They believe that they're supposed to be the rightful leaders of this new global order. The British century, the American century, now we're going to have the Chinese century. That's their vision.'

Captain Fanell said China purports to be 'economic partners' with island nations in the South Pacific, but 'the end result is they become your economic master'.

'With the flip at Kiribati and the Solomons, and what they're doing in Vanuatu, what they're doing in Fiji, you start to see a trend line here, which is that China is now taking control of the South Pacific,' he said.

'The Chinese are coming in with soft power and lots of cash to buy out local officials, to gain access to ports and airfields and resources that give them a controlling monopoly in the islands.'

He issued an alarming warning for Australia.

'People are starting to say, ''if we don't stand up and we will be ruled by them in another 25 or 30 years'',' he said.

Next in China's sights is war-torn Bouganville, which is set to hold a referendum to seek independence from Papua New Guinea next weekend and become the newest country in the Pacific since Timor Leste in 2002.

Former intelligence chief of the US Navy's Pacific Fleet, Captain Jim Fanell (pictured) fears China has Australia in its sights

A copper goldmine is set to become an integral part of a masterplan to rebuild Bouganville, where China has promised to build $1.47 billion worth of infrastructure, including new roads, an airport, a luxury resort, bridges and a port.

Former Bougainville Revolutionary Army general turned leading presidential contender Sam Kaouna has no problems with doing business with China if he becomes Bougainville's inaugural president.

'We are starting with a clean slate and looking at all avenue, China inclusive,' General Kaouna said.

'China is the superpower in the world. We are free. Bougainville is free to be choosing whichever countries we can have the best deal with.'

He's open to alliances with all countries but says he's still waiting on offers from the US and Australia on how they can support Bougainville.

He and his wife Josie were denied visas to Australia for more than 20 years as he called on Australia to do more, along with with an apology for its lack of support during its 10 year civil war with Papua New Guinea.

Destroyed by civil war, the Panguna Mine (pictured) is still a valuable commodity for Bougainville

'Australia is making an enemy out of Bougainville when they give me that treatment,' he said.

China's presence doesn't stop there.

Daniel Suidani, the Premier of the Solomon Islands' largest island Malaita, alleged he was offered a SI$1million (almost A$200,000) bribe to support his country's switch to China.

'Maybe there are some of my colleagues who have been offered the same and they may have accepted it … but I didn't accept it,' he said.

The Solomons' deputy opposition leader, Peter Kenilorea added: 'In terms of international diplomacy… it's a new way of doing things that is really dangerous.'

A flotilla of Chinese naval vessels held a 'live combat drill' in the East China Sea

On the nearby island of Tulagi, Chinese companies reportedly offered a 75 year lease that would have granted them rights to the island's deep-water port, oil, gas, fishing, forestry and tourism.

However, the land is owned by the women, where they had the final say to decide they didn't want to owned by the Chinese.

'Tulagi is very important to us, it's very important to us. It's a heart of the people,' voice of the people Margaret Manu said.

'China is a communist country. And the Solomon Islands is a democratic country.'