Taiwan's defence minister has backed a plan to deploy advanced missiles in the South China Sea over concerns that rival claimants to disputed islands are building up their arms, a legislator said Thursday.

Kao Hua-chu endorsed a proposal passed by the country's defence committee Wednesday demanding coastguard units in Taiping and the Pratas islands -- claimed by China -- be armed with Chaparral or Tien Chien I missiles.

"Minister Kao made it clear that he supports the proposal," he was quoted as saying in a statement released by Lin Yu-fang, the legislator from the ruling Kuomintang who pushed for the deployment.

Apparently mindful of rising regional tensions, Kao said the Taiwanese coastguards may need advanced weaponry rather than the Chaparral which Taiwan first acquired in the 1980s.

"Perhaps Tien Chien I or more advanced air defence missile systems should be given priority since the Chaparral is pretty old," Kao said.

The plan came following a report in July which found that Taiwan's coastguards in the contested waters were vulnerable amid mounting tensions.

Taiwan, Vietnam, Brunei, China, Malaysia, and the Philippines claim all or part of the Spratlys, which could lie on top of large oil reserves.

The Taiwanese coastguard currently has a 130-strong garrison on Taiping, the biggest island in the Spratlys archipelago.

Lin said the proposed ground-to-air missile deployment would be legitimate, citing the ministry's recent report on the military buildups by Vietnam and other neighbouring countries in the area.

Vietnam has deployed thousands of marines in the zone, backed Russia-made Su-27SK and Su-30MK2 fighter jets, Lin cited the report as saying.

"In stark contrast, the Taiwanese coastguards are only equipped with 20-mm air defence guns," he said in a statement.

The defence ministry added that in case of military conflicts, Taiwanese coastguards could hardly defend themselves against the Philippine forces equipped with naval gunboats, Lin added.