Jacinda Ardern has provided an update on the White Island eruption at her post-Cabinet press conference after receiving an update from officials. 

While it was initially believed there were approximately 100 people on or near the island at the time of the eruption, it is now believed there were fewer than 50. 

"A number of people are reportedly injured and are being transported to shore... Police are urging members of the public to avoid the Whakatane Heads and Muriwai Rd areas," Ardern said. 

"At this stage, it does appear to be a significant issue, particularly the scale of those affected at this stage."

The Prime Minister said she is not aware of any fatalities. She also said it's her understanding that tourists were involved. 

Ardern apologised for being late to the conference, saying she wanted to make sure she had "the most up-to-date information to share with you regarding the evolving situation at White Island". 

St John believes up to 20 people on the island require medical treatment.

The National Emergency Management Agency (NEMA) has issued a national warning for a moderate volcanic eruption. 

Seven helicopters have been dispatched to the island with paramedics on board.

St John believes up to 20 people on the island require medical treatment.

A police national command and coordination centre is being set up. 

Ardern said her "thoughts are with those affected". 

You can find more details here.