TAIPEI, Mar. 20 (Reuters) - Taiwan's foreign minister said on Wednesday that China has built "enormous" military bases on three islands surrounding Taiwan's main holding in the South China Sea, but Taipei is not looking to further escalate tensions in the strategic waterway.

Both Taiwan and China claim most of the South China Sea as their own territory, but Taiwan only controls one islet in the contested Spratly Islands deep in the southern part of the sea called Itu Aba, which Taiwan refers to as Taiping.

Some lawmakers from both the ruling and main opposition parties have called on President Tsai Ing-wen to visit Itu Aba before she steps down in May to assert Taiwan's sovereignty and view a newly renovated harbour that can take larger ships.

Both her predecessors visited the island but she has yet to do so while in office.

Asked by reporters about calls for Tsai to go to Itu Aba, Taiwan Foreign Minister Joseph Wu said there was no doubt the island belonged to Taiwan and the government would defend their sovereignty over it.

China and the Philippines have been involved in a dangerous stand-off in the South China Sea of late, but the situation around Itu Aba is also tense, Wu said.

"China has already created very enormous South China Sea military bases on the three islands surrounding Taiping - Subi Reef, Fiery Cross Reef and Mischief Reef - and these are all quite close to our Taiping," Wu said.

"As the dispute continues to intensify, we in Taiwan must consider how to use peaceful means to resolve the South China Sea issue, and not let others think we are creating difficulties."

If there is an opportunity, Taiwan will use the "best way" to demonstrate its sovereignty over Itu Aba, he added without elaborating.

Itu Aba has a runway long enough to take military re-supply flights from Taiwan, but is lightly defended compared to the nearby Chinese-controlled islands. Chinese forces generally leave Itu Aba alone.

China has carried out extensive land reclamation on its South China Sea islands, building major air force and other military facilities, causing major concern in Washington and around the region.

China says it has every right to build on and defend what it considers its territory.

Taiwan also controls the Pratas Islands in the northern part of the South China Sea, and both China's air force and navy regularly operate nearby to assert Beijing's territorial claims over Taiwan, which the government in Taipei rejects.

Vietnam, Malaysia and Brunei claim other parts of the South China Sea in dispute with both China and Taiwan.

Photo from Reuters