Scientists exploring a deep sea abyss for the first time have discovered a faceless fish.

Scientists onboard the CSIRO's Investigator are surveying Commonwealth marine reserves from northern Tasmania to central Queensland.

The crew dragged nets through a 4km deep abyss off Jervis Bay last weekend and caught a very unusual "faceless fish".

Di Bray from Museums Victoria told ABC that the finds so far had been "awesome".

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"On the video camera we saw a kind of chimaera that whizzed by - that's very, very rare in Australian waters," she said.

"We've seen a fish with photosensitive plates that sit on the top of its head, tripod fish that sit up on their fins and face into the current."

Bray said the faceless fish was "a highlight".

Scientists have found a 'faceless fish'. Photo / ABC
Scientists have found a 'faceless fish'. Photo / ABC

"Apparently, it's got eyes way under the surface but really you can't see any eyes," she said.

"We're collecting things we don't know from Australian waters.

"We think a lot of them are going to be new and we're not even scratching the surface of what we know about our abyssal plain fishes."