Civil Defence has cancelled a tsunami warning to beach and marine areas following an 8.1-magnitude earthquake in Mexico, saying the threat has now passed.
The warning had been in place since about 11.30pm on Friday night, for the waters of the Chatham Islands, the northern coasts of Hawke's Bay and the East Cape and Pegasus Bay on the South Island's east coast.
Civil Defence had warned of unusually strong and hazardous currents and unpredictable surges are expected in the water near beaches, and in harbours and estuaries.
It cancelled the warning at 11:30am, saying based on all available data the threat for the affected areas had passed.
"The largest wave amplitude of 35-40cm was recorded at the Chatham Islands. Observations from tidal gauges around other sites of New Zealand have shown maximum wave amplitudes of 15-25cm," it said.
It warned there was still a possibility of waves less than 20cm, and coastal areas would likely experience unusual, strong currents and surges lasting for several more hours.
The 8.1-magnitude quake has devastated parts of Mexico, killing at least 60 people.
Earlier yesterday evening, Civil Defence said there was no tsunami threat but it said after further modelling a beach and marine threat exists.
More detailed modelling overnight, based on buoy data as the tsunami activity moved across the Pacific confirmed the risk existed, Civil Defence said this morning.
Ministry director Sarah Stuart-Black said the unpredictable water activity could last for up to 24 hours.
"What it means is for people near waterways or on the beach, boaties going out [in the] morning, they need to be really aware of the fact that the water could be behaving differently."
Any currents or surges might not be obvious by just looking at the water, she said.
"But let's say you were out in waders, the current could be strong enough to knock you off your feet - it's that kind of behaviour that we're expecting."