Image copyright Getty Images Image caption The volcano erupted on Monday when dozens of tourists were on the island

Six bodies have been airlifted off the White Island volcano in New Zealand out of eight believed to have been left there after Monday's volcanic eruption.

The bodies have been flown to the naval vessel HMNZS Wellington.

The "high-speed" operation to recover the bodies was launched despite the risk of another eruption.

Dozens of tourists were visiting White Island when the eruption occurred - killing eight other people - 20 remain in intensive care with severe burns.

Conditions on the island were favourable, Deputy Police Commissioner John Tims said.

Relatives waited anxiously for the mission's return after earlier attending a blessing near the island.

Image copyright Reuters Image caption Relatives waited for the return of the rescue mission

Some 47 visitors from around the world were on the island when it erupted. Twenty-four were from Australia, nine from the US, five from New Zealand, four from Germany, two from China, two from the UK, and one from Malaysia.

GeoNet, New Zealand's geological hazard information site, said on Thursday there was a 50-60% chance of another eruption within the next 24 hours.

But families of the victims have been growing increasingly desperate for the bodies to be recovered.

"We are now living with a growing sense of desperation to bring home those that we know are there," Whakatane Mayor Judy Turner told reporters.

"The frustration of those families most affected is completely understandable."

What's the recovery plan?

Specialists from the New Zealand Defence Force went to the island on Friday morning to try to recover the bodies.

The team, kitted out with protective clothing and breathing apparatus, was flown from a naval frigate to the island on Friday morning local time.

If the volcano erupts while they are on the island they could face the danger of magma, superheated steam, ash and rocks thrown at high speed, volcanologists say.

Image copyright EPA Image caption Helicopters have been taking part in the operation

During the operation, a geologist is analysing real-time data to assess whether the mission needs to be aborted.

Deputy Police Commissioner Mike Clement told reporters that recovery efforts were going to plan but cautioned that there were "many things that could go wrong".

The fast recovery means there is less time to collect the evidence needed to ensure that the bodies are properly identified.

All of the bodies were within 200m (656ft) of each other, according to the New Zealand Herald.

Maori place ceremonial ban on volcano

Local Maori groups have placed a rahui over the waters around the volcano and the coastal stretch on the Bay of Plenty.

It is a traditional prohibition restricting access to an area. White Island, called Whakaari by the Maori, holds spiritual significance for the local Ngati Awa tribe.

The rahui was placed on Tuesday morning and will be lifted only once the missing bodies are recovered.

An expert from the Ngati Awa was expected to accompany authorities in the recovery mission.

Media playback is unsupported on your device Media caption "Toxic gases and ash": The BBC's Shaimaa Khalil flies around White Island

"Ngati Awa are front and centre of this operation so for the uplifting of the deceased, once that decision is made, Ngati Awa will be going across to Whakaari/White Island," deputy commissioner Wally Haumaha told RNZ.

Rahui are often placed on areas after deaths or accidents occur or to protect natural resources in a specific area. They are not legally binding but are commonly respected by New Zealanders.

What state are the injured in?

Many of the survivors are still in intensive care. Some have been unable to identify themselves because their burns are so severe, police say.

An estimated 120sq m of replacement skin will be needed for all the patients, according to Dr Peter Watson from New Zealand's National Burns Unit.

Surgeons in burns units around the country are working around the clock, authorities say.

Some of the Australian victims have been flown back to their home country, and more are expected to follow in the coming days.

White Island is a popular tourist destination off the northern coast of North Island, and there were day tours and scenic flights available.