Tonga was shaken by a pair of strong earthquakes just before midnight local time.
The US Geological Survey says the strongest was a magnitude 6-point-5 at a depth of 15.5 kilometres, 99 kilometres east northeast of Hihifo.
Half an hour earlier a shallower 6-point-4 tremor struck at a depth of 11 point 5 kilometres 109 kilometres northeast of Hihifo.
Tonga's national disaster office says there have been no reports of any damage.
The Pacific Tsunami Warning Centre said there was no tsunami threat from the quakes.