For Melbourne's Browitt family – mum Marie, father Paul and daughters Stephanie and Krystal – the 13-day cruise of the towns, sounds and seas of New Zealand was supposed to be the trip of a lifetime.

The hard-working family from the blue-collar suburb of Craigieburn had saved long and diligently to board Ovation of the Seas from Sydney on December 4, a family friend said.

Krystal Browitt is missing on White Island

But a week later, Paul and Stephanie are believed to be in comas in New Zealand hospitals with severe burns, and Krystal, 21, is among the Australians listed as missing and believed to be on White Island.

Devastated mother and wife Marie, a massage therapist by trade, stayed behind on the ship on Monday when her family took a day trip to explore the island's active volcano.