Taiwan's President Ma Ying-jeou defended his visit to a disputed island in the South China Sea Thursday despite criticism from the United States and protests from the other claimants as tensions swirl in the region.

Taipei insists Taiping Island in the Spratlys is part of its territory, but the chain is also claimed in part or whole by Vietnam, China, the Philippines, Malaysia and Brunei.

"We have the same general direction as the US and I don't see how my visit will heighten tension. I didn't go there to scold other countries," he told reporters on his return to Taipei Thursday evening, brushing aside rebukes from regional rivals.

The purpose of the trip was to visit Taiwanese personnel stationed there ahead of the Lunar New Year holiday, according to the presidential office, and Ma said the United States had been notified of the trip in advance.

"In the South China Sea if any country takes any action, many countries will protest and we will keep monitoring... I really can't see what they are protesting against," he said.

In a speech earlier in the day on Taiping, Ma said the islands were "an inherent part of the Republic of China (ROC)", using Taiwan's official title. "This is indisputable," he added.

Taiwan has been boosting its presence on the island, inaugurating a solar-powered lighthouse, and expanding an airstrip and a pier late last year.

But Washington, which has said it does not want to see an escalation of tensions in the region, said ahead of Ma's trip it was "extremely unhelpful", adding it would "not contribute to the peaceful resolution of disputes in the South China Sea."

His visit comes as several other claimants have been beefing up their military presence in the disputed region.

Beijing regards almost the whole of the South China Sea as its territory and other claimants have complained it is become increasingly aggressive in pressing its claim.

Ma made some effort at sounding reconciliatory on Thursday, calling for the setting aside of disputes and proposing joint exploration of natural resources the area is believed to harbour.

"To resolve disputes in the South China Sea, the ROC government will work to safeguard sovereignty, shelve disputes, pursue peace and reciprocity, and promote joint development," he said.

- Chorus of protests -

Ma faced an onslaught of criticism from other countries who make claim to the islands, including Vietnam.

Foreign ministry spokesman Le Hai Binh said the visit was a "serious violation of Vietnam's sovereignty, running counter to recent speeches from Taiwan which express wishes to contribute to maintaining peace and stability" in the disputed sea.

Le called on Taiwan "not (to) repeat similar acts which escalate tension", with Ma's visit coming weeks after Taiwanese coastguards drove off a Vietnamese fishing boat near Taiping Island.

The Philippines expressed similar sentiments, saying Taiwan should resist provoking its neighbours.

"We remind all parties concerned of our shared responsibility to refrain from actions that can increase tension in the South China Sea," foreign ministry spokesman Charles Jose said.

China, which also regards Taiwan as part of its territory awaiting reunification, gave a measured response to Ma's trip.

"The Nansha (Spratly) islands have been Chinese territory since ancient times. The Chinese people on both sides of the Taiwan Strait all have the responsibility to safeguard the ancestral property of the Chinese nation," Chinese foreign ministry spokeswoman Hua Chunying told reporters.