The minute of silence was held at 2.11 p.m. (local time), the same time the volcano erupted on December 9, reports Efe news.
Prime Minister Jacinda Ardern and her Cabinet paid tribute to the victims, while the Whakatane community gathered in the bay overlooking Whakaari/White Island to pay homage, joined by many people in other parts of the country.
There are currently two investigations underway - one by police on behalf of the coroner, and one by WorkSafe, New Zealand's workplace health and safety regulator, which could take for a year, Ardern said.
However, she did not rule out further inquiry as Cabinet gathers advice from officials.
"As a Cabinet we know that it's possible there will be broader issues that won't be covered by these inquiries. Therefore I have asked for advice from officials to look into whether there are any gaps that need to be addressed that fall outside of a potential coronial inquiry and the WorkSafe investigation," Ardern said during a post-cabinet press conference.
"What I want to ensure is that we answer all the questions that need to be answered, to try and do that with as little duplication as possible," she added.
Ardern also announced that Cabinet had approved NZ$5 million ($3.3 million) package to help small businesses affected by the tragedy and the suspension of tourism activity on Whakaari.
Whakaari suddenly erupted when 47 people - 24 Austral, two Britons, four Germans, five New Zealanders, nine Americans, two Chinese and one Malaysian - were on hiking trip on the privately-owned island located 40 km north of Whakatane on New Zealand's North Island.
Also on Monday, New Zealand Police released the names of four identified victims. They are Austral Jessica Richards, 20, Jason David Griffiths, 33, Martin Berend Hollander, 48, and Kristine Elizabeth Langford, 45.
They add to those already identified: New Zealander Tipene James Te Rangi Ataahua Maangi, 24, and Austral Berend Lawrence Hollander, 16, Matthew Robert Hollander, 13, Anthony James Langford, 51, Karla Michelle Mathews, 32, Zoe Ella Hosking, 15, and Gavin Brian Dallow, 53.
Fourteen people remain hospitalized, most of them in critical condition with severe burns, at medical centres in New Zealand, while another 12 continue to fight for their lives in Australia.
The search for two missing continued on Monday.
The 321-metre-high Whakaari, 70 per cent of which is below sea level, is considered one of New Zealand's most active volcanoes and a tourist attraction.
Located at the southeastern end of the Pacific Ring of Fire, Whakaari last erupted in 2016 without causing fatalities.
The deadliest incident at the site occurred in 1914 when 10 miners died as a result of a landslide caused by the collapse of part of the volcano's crater.
( With inputs from IANS )