Lombok was hit a week earlier by a 6.4 quake that killed 16 people.
About three-quarters of the island's rural north have been without electricity.
Rescuers intensified efforts Wednesday to find those buried in the rubble, with volunteers and rescue personnel erecting temporary shelters for the tens of thousands left homeless on the southern island.
The aftershock had caused more "trauma", said national disaster agency spokesman Sutopo Purwo Nugroho.
Officials said the quake's epicenter was on land and so there was no risk of a tsunami.
The US Geological Survey said the quake, felt on the nearby holiday island of Bali, measured 5.9 on the Richter scale.
The number of confirmed deaths from an quake that hit the Indonesian island of Lombok on Sunday has risen to 259 and would rise as more victims are found in the rubble, the disaster mitigation agency said.
Many people on the island have been using Facebook's Safety Check feature - launched in 2014 - which allows users to notify their friends and relatives that they are safe after disasters.
Facebook has apologized after it emerged that one of their automatic celebration animations had been triggered by messages about Sunday's deadly natural disaster in Indonesia. "Then finally you see on Facebook that they are ok - and then you see balloons", she said.
Cleanup and rescue efforts are still continuing on the island, following the previous quakes.
The official death toll stands at 131, but local media are reporting figures as high as 347.
The government says more than 1,400 people were injured and more than 156,000 displaced.
Indonesia is prone to earthquakes because of its location on the "Ring of Fire", an arc of volcanoes and fault lines in the Pacific Basin.
Meanwhile, the evacuation of thousands of tourists from the Gili Islands - three tiny, coral-fringed tropical islands off the northwest coast of Lombok - has finished, officials said.
There have been 355 aftershocks since the last quake happened on Sunday, which killed at least 131 people.
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