The shallow quake hit at a depth of nine kilometres (five miles) at 2307 GMT around 75 kilometres southeast of the nearest main city of Kendari, the US Geological Survey said, putting the size of the tremor at magnitude 6.2.
Indonesia's Meteorology and Geophysics Agency measured the quake at magnitude 6.0 and said it hit about 55 kilometres southeast of Kendari at a depth of 18 kilometres.
"The tremor was felt in Kendari city but there was no report of damage," agency official Lukito, who goes by one name, told AFP adding that there no danger of a tsunami as the quake's epicenter was on land.
The quake was followed by an aftershock measuring 5.2.
Indonesia sits on the Pacific "Ring of Fire", where the meeting of continental plates causes high seismic activity, and is frequently hit by earthquakes.