Prime Minister Jacinda Ardern says there will be an inquiry into the tragedy at Whakaari/White Island.
Forty-seven people were visiting the active volcano on Monday when it erupted. Five people have been confirmed dead with eight more missing, believed dead.
There has been anger people were allowed on the island despite warnings in recent weeks of increased volcanic activity.
Ardern told The AM Show on Tuesday there will "absolutely" be an inquiry into what happened.
"Questions will need to be answered, obviously," Ardern said.
Earlier at a press conference, Ardern told reporters the focus now was on the recovery mission.
"Look I expect there will be lots of questions that need to be asked in that regard, but the consensus here is the focus has to be on those who are critically injured and of course what is a recovery mission," she said.
She added the island had been a tourist attraction for more than 30 years and was an unpredictable destination.
GeoNet raised the volcanic alert level at White Island recently to level 2. Level 5 is the highest.
Increased levels of sulphur dioxide gas and tremors were also reported.
White Island Tours on Monday was asked if it was safe to travel to the island. Newshub was referred to Bay of Plenty Tourism, which didn't respond.
White Island Tours is owned by Ngāti Awa Holdings. Company chair Paul Quinn told Radio New Zealand the warnings in recent weeks "didn't meet its threshold for stopping operations".
On its website, White Island Tours says "passengers should be aware that there is always a risk of eruptive activity regardless of the alert level".
Quinn said level two volcanic activity was still considered safe to visit the island.
"It's been level two for about a week, as I understand it," he told TVNZ's Breakfast.
"This is a big tragedy, unfortunately, for us."