Thailand Thursday expressed impatience at continuing insurgent violence in its Muslim-majority south as delegates began a third round of peace talks in the Malaysian capital with the rebels.

Thai National Security Council chief Paradorn Pattanatabut told reporters he needed "concrete outcomes" to violence that has killed more than 5,500 in the past decade "so I can answer to the people".

"Our agenda is to reduce violence in a particular timeframe or by area. Today we must get clear answer on the facts (behind the recent spike in violence)," Paradorn, Bangkok's lead negotiator, said before meeting rebel representatives.

Talks which began on March 28 have so far failed to end near-daily violence in the three provinces bordering Malaysia.

Thai authorities had floated the idea of handing some local decision-making to the provinces dominated by ethnic Malay Muslims. But Paradorn said the issue was unlikely to come up in this round, which would be dominated by the violence.

Five Thai security personnel were killed in a fresh spate of gun and bomb attacks two weeks ago, which the government blamed on insurgents seeking to disrupt the fragile peace process.

Despite two rounds of peace talks since March, near-daily bloodshed has raised questions over how much control rebel leaders have over radical militants.

But a Thai delegation official expressed confidence Thursday that "they are the real representatives of all groups" in southern Thailand.

"Every group, they are now together. They are talking to us," said deputy permanent secretary for defence Nipat Thonglek.

The rebels had in April demanded "liberation" from the Thai kingdom and made a series of demands. But Paradorn has insisted that discussions are not about autonomy but about local administration.