No damage has been reported in Hawke's Bay overnight after the 7.5 magnitude earthquake near Hamner Springs shortly after midnight, but people have been warned to stay away from beachs as a tsunami warning is still in place.
The earthquake caused widespread damage across the South Island and in Wellington.
The earthquake triggered a tsunami alert for the east coast of both islands and in Hawke's Bay coastal areas like Waimarama, Ocean Beach, Te Awanga and Westshore were evacuated.
The modelling showed that the wave would not be large and so a wider evacuation was not required.
"That means we made a conscious decision not use the sirens. To do so could have panicked a whole population for no good reason and the results could have been worse than the impact of the small wave predicted at that time. The areas were small and therefore we could door knock those people easily," said Hawke's Bay Civil Defence group controller Ian Macdonald.
"Having said that, we are very pleased at the number of people who self-evacuated. While in the end the threat did not eventuate this time, it is really pleasing to know that people know what to do.
"There may be a time when a local earthquake causes a tsunami so suddenly that we don't have time to warn anyone. People should not wait for a siren or a knock on the door: If you feel an earthquake that is 'long or strong, get gone' is the message."
The threat of a tsunami making landfall was gone by 5.45am, and the last of the evacuated residents advised that they could safely return home.
Mr Macdonald acknowledged that at times it seemed there were mixed messages, but that was "the nature of the beast" in that no two emergencies are the same and information changes as events unfold.
"Nature doesn't give us notice and doesn't tell us what sort of affect she's going to have.
"This was a very long rupture of about 100km long so it was impossible in a very short amount of time to say exactly what would happen along the length of our country.
"The best we can do is give people what we know, ask that they make some decisions on the best way to react, and then keep updating them as clearer information comes to hand."
As today progresses, he asked that people remain aware of any Civil Defence messaging, in case further earthquakes changed the situation.
However, the Ministry of CD is keeping a tsunami marine and beach threat from Napier to north of Dunedin in place, and they advise these areas can expect unusually strong currents and unpredictable water flows near the shore, the Hawke's Bay Civil Defence has said.
In a post on its Facebook page, the Hawke's Bay Civil Defence Emergency Management Group said this meant there was a threat to beach, harbour, estuary and small boat activities so people were advised to stay away from red zones while this warning was still in effect.
Hastings Mayor Lawrence Yule said it was the longest quake he had felt.
"It was not a jolting one, but was very long and severe."
"To have felt it like that when the earthquake was so far away, meant it was a very big quake."
Mr Yule said his first concern had been the threat of a tsunami.
"I am always concerned about a tsunami because a quake of that size will always cause a tsunami."
He said the Bay was "always prone to tsunamis" because of its proximity to the Kermadec Trench.
People should always self-evacuate with the threat of a tsunami.
Earlier residents in the Bay reported feeling a strong, prolonged shake and a tsunami warning for the entire New Zealand East coast, including East Cape and the Bay, was put in force.
Hawke's Bay Today received a number posts on its Facebook page from readers who described their experience. Many were in bed and either took cover in doorways or went outside. The quake was felt from Wairoa to Dannevirke.
Hawke's Bay Civil Defence Management Group ordered the evacuation of low lying areas and many residents were woken in the early hours and moved to higher ground.
A group of German freedom campers on Marine Parade made their way up Bluff Hill, while Haumoana School hall was a hive of activity where residents of Haumoana and Te Awanga were evacuated to.
Soon after 5.30am Hawke's Bay Civil Defence Management Group's facebook page (http://www.civildefence.govt.nz/resources/active-emergencies/cheviot-earthquake/) reported that those who were evacuated could go home if they lived outside red zones of parts of Te Awanga, Waimarama, Ocean Beach and one street in Westshore (Meeanee Quay from James St to Whakarire Ave).
"Wairoa Civil Defence is looking after the people in its area who are near the beach. The situation could change if there are further earthquakes so please remain aware," the site said.