The latest quake on Thursday was felt strongly on the island and followed a 6.9 quake on Sunday that killed at least 131 people and damaged thousands of houses.
A resident shows a photo of missing victims believed to be trapped inside a collapsed building, as rescue workers continue searching after Sunday's natural disaster in Pemenang, North Lombok, Indonesia on August 8, 2018 in this photo taken by Antara Foto.
The Red Cross previously said aid was struggling to reach the northern parts of the island due to debris from the quake and the ongoing risk of landslides.
There have been 355 aftershocks since the last quake happened on Sunday, which killed at least 131 people. After the 6.9 magnitude quake in Lombok, Facebook users wrote "I hope people will survive". He told the Jakarta Globe that "residents panicked and ran from their shelters" and "several buildings were further damaged".
Indonesia's chief security minister Wiranto, who like many Indonesians goes by one name, said the latest figures before the third quake suggested 319 people had died.
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Makeshift medical facilities have been set up to treat the injured.
National disaster agency spokesman Sutopo Purwo Nugroho said people ran onto roads in panic and buildings were damaged, causing more "trauma" for people on the island.
Motorcycles parked on the street in northern Lombok's Tanjung district toppled over and the walls of some nearby buildings collapsed.
The national disaster agency said there are still some evacuees that have not yet received aid, especially in the north and west of the island. Some villages have collapsed entirely.
Sunday's quake also sent some 2,500 people to hospital with serious injuries and drove more than 156,000 people from their homes.
Thousands of tourists have also left Lombok since Sunday, fearing further earthquakes, some on extra flights provided by airlines and others on ferries to the neighbouring island of Bali. "The grandson tried to help the grandmother to get out but he pushed too hard", she said.