By Phil Mercer
BBC News, Sydney
China's Vice-Premier Zeng Peiyan has completed a brief tour of the South Pacific, showing how important the region is to Beijing.
The rivalry sparked tensions in the Solomons' capital in 2006
China is competing with Taiwan for diplomatic recognition as well as access to vast reserves of fish, minerals and timber.
But there are concerns that this fierce rivalry is unsettling and that bribes are making the region more corrupt and violent.
"The countries of the South Pacific are micro-states and many of them have weak governments, so the Taiwan-China competition often has quite destabilising effects on the small, often not-very-well-run governments," warned Dr Malcolm Cook from the Lowy Institute for International Policy.
Professor Stuart Harris, a former senior foreign affairs official in Canberra, said this diplomatic arm-wrestle between Taiwan and China was a big worry.
"It's making life very difficult," he said.
"You don't need to spend a lot of money to buy a government, and corruption is becoming even more endemic."
Taiwan and China have been governed separately since the end of a civil war in 1949, and both still compete for diplomatic recognition.
Most countries recognise China, but Taiwan has the recognition of 24 nations, of which six - those in Kiribati, the Marshall Islands, Palau, Nauru, Tuvalu and the Solomon Islands - are in the South Pacific.
Beijing has more friends in the neighbourhood. It has formal ties with eight countries, including the largest island nations, Fiji and Papua New Guinea.
China also has strong diplomatic relationships with Australia and New Zealand.
Loans and other investments, as well as the construction of roads and sporting facilities, are used by both sides to foster loyalty.
Given the importance of the region to Taiwan, analysts have detected desperation in its recent efforts.
There were claims that Taiwanese money was used to bribe politicians during an election in the Solomon Islands last year.
Riots broke out in the capital Honiara when Snyder Rini was appointed Prime Minister.
He later resigned amid allegations he used money from local Chinese businessmen and Taiwan to buy the support of MPs.
Mr Rini denied the allegations, and the Taiwanese government vehemently rejected accusations that it had tried to influence the political process.
Not everyone was convinced.
At the time Joses Tuhanuku, the President of the Solomon Islands Labour Party, told Australian television that the election had been tainted by kick-backs.
"It has been corrupted by Taiwan and business houses owned by Solomon Islanders of Chinese origin, and they knew there was a lot of money going around to bribe the new members and some of the old members to put up this prime minister," he said.
Australia has warned both China and Taiwan not to interfere in the politics of its regional neighbours.
Dr Cook says the rivalry is destabilising
"We don't want to see chequebook diplomacy entering the Pacific," said foreign minister Alexander Downer.
That is a forlorn hope, according to Dr Cook.
"Often even in one district (during the Solomon Islands election in 2006) more than one candidate claimed to have received funding from the Taiwan government, so if these stories are true the depth of the involvement in the Solomon Islands by Taiwan was something that's not seen in many other places," he said.
Allegiances can change - Kiribati turned its back on China in favour of representations from Taiwan.
But China's growing economic power makes it unlikely that others will follow.
Professor Stuart Harris said many countries were feeling a "strong gravitational pull towards China."
Andrew Tumbo, Papua New Guinea's Deputy High Commissioner in New Zealand, said trade was at the heart of his government's ties with Beijing.
"Papua New Guinea is rich with resources and China is talking resources from all parts of the world and we can all benefit," he said.