It sounds like the stuff of a Jules Verne novel — a voyage to the bottom of the sea.

But in a first, a team of scientists is preparing to survey the darkest depths off the coast of Australia.

Twenty-seven scientists from seven countries and 13 support crew will spend 31 days aboard the country's only dedicated research vessel, The Investigator.

They depart from Launceston and finish at Fraser Island, and will stop at seven marine sites along the way to take samples at a depth of 4 kilometres at each one.

The data collected will help scientists learn more about biodiversity and the challenges such habitats face by the threats of climate change, rubbish, pollution and other human activity.

"We know exactly what occurs at those depths in some other places like the North Atlantic, and around Japan and perhaps some other areas as well," said the expedition's chief scientist, Tim O'Hara.

"But it's never really been investigated in the Southern Hemisphere so there will be a complete element of surprise."

The abyss is defined as more than 3.5 kilometres deep, but in some parts of the ocean it gets as deep as 11 kilometres.

Scientist Tim O'Hara says deep seas around Australia have never been properly investigated. ( Supplied: Matthew Newton )

There are about 8 million square kilometres of deep sea in Australian oceans, more area than the country's dry land.

"Most of the very deep sea is very fine mud, but there are canyons that are so deep they could swallow Mount Everest," Dr O'Hara said.

"There's dead and even live volcanoes that are rising from the deep sea."

'There'll be a whole bunch of really awesome weird stuff'

It takes the ship's sampling gear between six and eight hours to reach the sea floor at a depth of 4 kilometres.

"It's way too deep for a person to go down, they'd just be crushed to a leaf if they went down that far," Dr O'Hara said.

"So what we're going to do is the old-fashioned technique of putting a metal box on a long wire behind the ship, grabbing a bit of the sea floor and bringing it to the surface."

The scientists will do 12-hour shifts between 2:00am and 2:00pm — or the reverse — to sort and identify the specimens.

The conditions are so difficult in the abyss that not many creatures can survive, and many of the animals evolve without eyes because it is so dark they cannot see anyway.

Most of them are pale or red, and some produce their own light through bioluminescence.

Because the water pressure is so intense, many are jelly like, and quite small.

The conditions are so difficult in the abyss that not many creatures can survive. ( Supplied: David Paul )

Dianne Bray of Museums Victoria, a self-described "fish person" who will also be on the voyage, expects one third to a half of the samples they collect will be new species.

"There'll be a whole bunch of really awesome weird stuff," Dr Bray said.

"Things like tripod fish, which are those fish that stand up on their fins and face into the current.

"Things with big teeth. Deep sea lizard fishes with jaws full of snaggly teeth. Maybe rat tails, which are fishes with big pointy snouts."

According to Museums Victoria, the voyage will be one of national significance, but it also aims to get Australians more excited about marine science.

"I love being at sea," Dr Bray said.

"Being out there, watching the sea birds and just seeing what comes up from the deep sea is just awesome. I love seeing these weird and wonderful things coming up."