Indonesian prison authorities Friday warned dozens of inmates who escaped during a massive quake, including paedophiles and drug offenders, that they would be shot if they resisted arrest.

Some prisons in Aceh province, where 170,000 people were killed in a 2004 tsunami, evacuated inmates Wednesday when an 8.6-magnitude earthquake jolted Sumatra island and triggered an Indian Ocean-wide tsunami alert.

Twenty-nine inmates from Sigli Prison, 50 kilometres (30 miles) from the provincial capital Banda Aceh, made a getaway and were still on the loose Friday afternoon.

"We are giving the prisoners a deadline of this evening to return. If we find them and they try to flee, the guards and police are allowed to shoot," warden Djoko Budi Setianto said.

"Most of them are drug offenders. One was involved in a robbery case and some others are involved in paedophilia," he said, adding that two prisoners had called and promised to return.

Guards at the prison, near the coast, evacuated all 221 inmates during the hours-long alert, with memories of the 2004 destruction that destroyed the jail fresh in people's minds.

"The two guards who opened the gates to let the prisoners out on Wednesday were caught in the 2004 tsunami, but they survived. They are still traumatised by it," Setianto said, adding there was little damage to the prison from the latest quake.

But Banda Aceh Prison on the outskirts of the capital did not escape unscathed.

One of its walls crumbled when the quake hit, and inmates were out playing football and volleyball on the prison field.

Prison chief Ridwan Salam said the inmates panicked during the first jolt, which rumbled for five minutes.

They sat together in a field to pray.

"They raised their hands in the air and continually chanted 'la ilaha illallah' (there is no God but God)," Salam said.

"Some were so emotional they started crying as they prayed," he said.

The prison originally sat just metres (yards) from the coastline, but was completely destroyed by the 2004 wave, which killed 350 of the 400 inmates trapped in the building as it filled with water and collapsed.

It has been rebuilt around five kilometres (three miles) inland.

People who had heard false reports that the prison had been destroyed came to search for their loved ones Thursday.

"At least 150 family members came to the prison. When they found their loved ones they were so relieved they hugged one another and cried," he said.