Tuvalu’s support comes just two months after fellow Pacific island nations Kiribati and Solomon Islands switched their diplomatic recognition to China.
Tuvalu's foreign minister said on Thursday the South Pacific nation had rejected offers from Chinese companies to build artificial islands to help it cope with rising sea levels, an approach viewed as undermining Taiwan's influence in the region.
Tuvalu foreign minister Simon Kofe instead explicitly expressed support for Taiwan and said his country was working to set up a group uniting Taiwan's remaining four allies in the Pacific.
"Tuvalu and Taiwan diplomatic ties are strongest they've ever been," Kofe told Reuters in an interview in Taipei.
"We believe in the power of grouping together and collaborating," he added, referring to the Marshall Islands, Palau and Nauru as well as Tuvalu. "Together with our partners, we will be able to counter the influence from mainland China."
The show of support provides some relief for Taiwan President Tsai Ing-wen, who is seeking a re-election in January and has seen seven countries drop Taiwan as a diplomatic ally since she took office in 2016.
Tuvalu's support comes just two months after fellow Pacific island nations Kiribati and Solomon Islands switched their diplomatic recognition to China.
Beijing has in recent months stepped up a campaign to peel away more allies of self-ruled Taiwan, which Beijing considers its territory and therefore ineligible for state-to-state relations.
Taiwan clamed that Kiribati was lured by Beijing with the promise of airplanes, while the Solomons was offered development funds.
Kofe told Reuters that Chinese companies had recently approached local communities to help support a $400 million government plan to build artificial islands, saying he believed the companies were backed by the Chinese government.
"It's a no from us," Kofe said. "We are hearing a lot of information about debt, China buying our islands and looking at setting up military bases in our part of the world. Those are things that are concerning to us."
"We hope those are lessons for other countries to be careful and be conscious of those negative impact...It's not good for our Pacific fellow brothers and sisters."
China's moves to expand its influence in the Pacific have alarmed the United States and its allies, including Japan, Australia and New Zealand. The group has dominated the strategic waters of the small developing nations since World War Two and are pushing back against Beijing's moves.
The premier of the Solomon's Malaita province told Reuters on Thursday that the United States and its regional allies have pledged to develop a deep-sea port and will be invited to patrol its territory, creating a beachhead against increased Chinese investment.