At least two people have been killed and 36 others injured in a car-bomb explosion outside a hotel in a commercial district in southern Thailand, police say.

The explosives were hidden in a lorry parked across from the Hotel Holiday in Yala province's Betong district on Friday, said Wasan Phuangnoi, a local police official. At least three of the wounded were reportedly in critical condition.

Authorities said they had been on alert for a possible attack towards the end of the fasting month of Ramadan in the Muslim-majority region, where armed factions have fought for autonomy.

"We did not expect unrest to cause as much damage in Betong as this," said Banphot Phunphian, a spokesman for the Thai military.

More than 6,000 people have been killed since 2004 in near-daily bombings and shootings in the region near Thailand's southern border with Malaysia.

Victims often include Buddhists and Muslims.

Peace talks between some rebel factions and the Thai authorities stalled as a political crisis erupted in Bangkok last year, culminating in a military coup in May.

Many local Malay-Muslim accuse the authorities of widespread human rights abuses and a lack of respect for their religion, culture and language.