Guatemala City (AFP) - A closed-door retrial of Guatemala's former military dictator Efrain Rios Montt on charges of genocide was suspended on Wednesday after plaintiffs won a battle to have his case judged separately from that of his intelligence chief.

Rios Montt is accused of being ultimately responsible for the murders of 1,771 indigenous Ixil-Maya people in 1982-1983, at the height of Guatemala's 36-year civil war which ended in 1996.

Now aged 89, he had been on trial in absentia since March 16 in Guatemala City. His attorneys say he suffers from dementia and is too ill to attend.

A May 2013 trial delivered a conviction and an 80-year sentence, but that was overturned days later by Guatemala's constitutional court, which ordered the new trial.

Hector Reyes, a lawyer for the families of Rios Montt's alleged victims, told AFP the retrial was suspended because the families had won an appeal to have Rios Montt's case handled separately from that of his ex-intelligence chief, Jose Rodriguez, who faces the same charges but in open court.

No date was given for when the retrial might resume.

Other legal challenges still hanging over the retrial include one from Rios Montt's lawyers arguing that their client is too senile to be judged.

According to the UN, some 200,000 people died or were made to disappear during the Guatemala's long, brutal civil war.

Rios Montt is accused of orchestrating an extermination policy against the indigenous population, which was perceived to be collaborating with leftwing guerrillas waging war with government forces.

Should he be convicted again, he would be subject to detention in line with his health condition, meaning possible hospital internment or home confinement.

Rios Montt in March 1982 deposed Lucas Garcia, who went on to die in exile in Venezuela in 2006 aged 81.