China was Tuesday on a diplomatic collision course with some of its neighbours and the United States over its controversial island-building, as regional security talks opened in Kuala Lumpur.

Beijing is expanding tiny reefs in the flashpoint South China Sea into islands and topping some with military posts to reinforce its claims over the strategic waters, fanning fears of a conflict.

Ahead of the gathering hosted by the 10-member Association of Southeast Asian Nations (ASEAN) that kicked off on Tuesday in Malaysia, Chinese Foreign Minister Wang Yi signalled no compromise.

During a stop in Singapore on Monday, Wang insisted that the issue should not be raised at the talks, and that it would press ahead with its controversial island building.

"China has never believed that multilateral fora are the appropriate place for discussing specific bilateral disputes," Wang told reporters before travelling to Malaysia.

Attempts to bring the issue up are "counter-productive" and "heighten confrontation", he warned.

Adding to the tensions, a Washington-based think tank said this week Beijing could be preparing to build a second airstrip on an artificial island.

China is already building a 3,000-metre (9,842 feet) runway on Fiery Cross reef, which could ultimately be used for combat operations, according to the Center for Strategic and International Studies (CSIS).

Wang said China would not agree to suspend island building, as demanded by some rival claimants and the United States.

"The freeze proposal may seem even-handed on the surface but it is actually unrealistic and will not work in practice," he said.

However US and Southeast Asian officials say the hot-button issue will be raised in Malaysia this week.

Formal meetings that opened on Tuesday involved just ASEAN foreign ministers.

The discussions, known as the ASEAN Regional Forum (ARF), will expand over the following two days to include US Secretary of State John Kerry, Wang, and envoys from the wider region including Japan, the Koreas, Russia and elsewhere.

Beijing claims control over nearly all of the strategically important South China Sea, a key shipping route thought to boast rich oil and gas reserves.

Vietnam, the Philippines, Malaysia and Brunei -- all ASEAN members -- also have various claims to the South China Sea, as does Taiwan.

Beijing has long insisted that any disputes over the waterway must be handled on a bilateral basis with rival claimants, rather than with a united bloc.

Wang is expected to meet with Kerry on Wednesday morning on the meeting's sidelines.

Kerry arrives later Tuesday and will meet with his Turkish counterpart Mevlut Cavusoglu, as both sides grapple with the threat posed by the Islamic State.