A magnitude 6.0 earthquake near the Kermadecs tricked sensors on Monday into thinking there was an even bigger quake just off the New Zealand coast.
The US Geological Survey said the tremor in the Kermadec Islands, about 1000km northeast of New Zealand, occurred at about 4.16pm on Monday at a depth of about 325km.
It was about 112km from the nearest populated area at L'Esperance Rock.
AAP reports the quake was strong enough to fool sensors in New Zealand, where GNS Science reported two quakes measuring 6.0 and 6.3 just off the east coast of the North Island at about 4.20pm.
However, it quickly tweeted that they were a misreading.
"Sometimes we do get events like that, it's difficult for our network," GNS Science duty seismologist Anna Kaiser told AAP.
Because two different waves arrived at separate times the sensors were tricked into thinking the single distant large event was actually two separate closer events, she said.