New Zealand Prime Minister Jacinda Ardern said Monday that official inquiries into last week's fatal volcano eruption could take up to a year, and will carry potential criminal penalties of up to five years in jail.

Ardern also announced a 5 million New Zealand dollar ($3.2 million) fund to help small businesses affected by the eruption, after New Zealanders held a minute of silence to honor the victims a week on from the tragedy.

The official death toll from the surprise eruption on White Island, also known by its Maori name of Whakaari, stands at 16. Two people whose bodies are believed to be in the waters around the island are still officially listed as missing.