Sydney Teen Winona Langford Still Missing After NZ Volcano Blast

Winona Langford, 17, is one of two people still missing eight days after the devastating volcano eruption in New Zealand.

The Sydney woman's body is believed to be buried on White Island or in the sea.

Langford's parents Anthony and Kristine were killed in the eruption, while her brother Jesse, 19, remains in hospital. His injuries are reported to be critical.

In a statement on Monday, the Langfords were remembered as "loving parents" to their teenagers and a "wonderful couple".

"Anthony and Kristine, loving parents to Jesse and Winona, were a wonderful couple and devoted to both their immediate and extended families," the statement read.

On Friday a recovery team retrieved six bodies from the island, but Langford and New Zealand-based tour guide Hayden Marshall-Inman were nowhere to be found.

Police and dive squads conducted a number of subsequent searches over the weekend while a defence force helicopter was sent to the island on Tuesday. It was, however, forced to turn back due to poor weather.

"Conditions are being assessed to determine the viability of a second attempt by Eagle or a shoreline search by boat later this morning," New Zealand police confirmed.

The Police National Dive Squad will not enter the water on Tuesday.

On Monday, hundreds of mourners gathered in New Zealand for a minutes silence, in honour of the victims.

To mark one week since the blast, Prime Minister Jacinda Ardern posted an emotional tribute to Instagram.

"Lives were lost immediately, and in the days that have followed others have succumbed to their injuries. There are almost no words for the stories of both the aftermath and the loss that has followed," she wrote.

"Those who have been lost are now forever linked to New Zealand, and we will hold them close."

The death toll sits at 16, but is expected to rise.

Twelve people are being treated in Australian hospitals after being repatriated with severe burns.

It's understood all were on a tour to White Island from the cruise ship Ovation of the Seas, which docked in Sydney Harbour on Monday.