Seven officials will face trial over the deaths of scores of Muslim protesters who suffocated in army trucks almost two decades ago in Thailand's deep south, a lawyer for the victims' families said Friday.

Known across the kingdom's insurgency-scarred south as the "Tak Bai massacre", the incident on 25 October 2004, remains one of the deadliest in a rebellion by Malay Muslims against the ruling Thai state, which colonised the provinces bordering Malaysia over a century ago.

Seventy-eight people suffocated after they were arrested and stacked on top of each other in the back of Thai military trucks.

The officials will also face trial over the deaths of seven others who were shot as security forces used live rounds on a large crowd of protesters calling for the release of several detainees.

Narathiwat court in the south accepted on Friday a petition submitted by the victims' families seeking to prosecute seven officials for murder and attempted murder, Ratchada Manuratchada, the lawyer representing the families, told reporters.

The decision comes two months before the statute of limitations on the case is due to expire -- 20 years after the deaths.

"The court has agreed to take the case to trial," Ratchada said after the court decision.

"This is an historic case in our country which will decide if authorities treated civilians appropriately." 

No member of the Thai security forces has ever been jailed for extrajudicial killings or torture in the "deep south", despite frequent allegations of abuses across the region.

The seven defendants include senior military officers and politicians.

The incident happened while former prime minister Thaksin Shinawatra was in office and Prawit Wongsuwan, now a senior politician, was army chief.

The plea hearing is scheduled for September 12.

A low-level conflict has rumbled in the southernmost provinces since the massacre, killing more than 7,000 people as militants in the region continue to battle for greater autonomy from the state.

The region -- which is culturally distinct from Buddhist-majority Thailand -- is heavily policed by Thai security forces.