Civil Defence has declared its emergency alert test a success, with people in all regions with cellphone coverage across the country receiving their message.

Photo: Supplied

Director Sarah Stuart-Black said about a third of mobile phones were enabled to receive the notification, which is about two million handsets.

"We've had confirmation from each of the regions in the North and the South Island that the messages had been received into those regions," she said.

Ms Stuart-Black said if people did not receive the alerts, which were sent out between 6pm and 7pm, they should not feel concerned.

"This is a new channel in addition to the many other ways we communicated with New Zealanders radio, tv, social and now this," she said.

After tonight's test, more than 10,000 people filled out an online feedback form and the Civil Defence website had more than 100,000 visitors.

Ms Stuart-Black said the survey will collate where people were at the time the alert was sent and what type of handset they used.

"We understand already from some of that feedback online that there has been some variability how some handsets have behaved so we're hoping through that survey that we'll have that information about how the message was received," she said.

The message was received by mobile phones that were switched on, within the target area, and capable of receiving it.

The message sent automatically and people did not need to sign up or download any app to receive it.

Those wanting to know whether their phone can receive the message can check online.

Civil defence said it expected the number of phones capable of receiving the message to increase over time as people replaced their phones with newer models.

Last month many people were woken up when test alerts were accidentally sent out in the early hours of the morning.