The 2014 disappearance of Malaysian Airlines flight MH370 remains one of the greatest mysteries in aviation history.

Now, scientists believe they have narrowed down the potential search area to a fraction of space that was searched in December 2016.

CSIRO researchers say they are more confident than ever in the precise location, which has been missed by the work that scoured the ocean floor, as well as the aerial surveillance.

But how did they get to this point?

Investigators have known for some time that the plane crashed somewhere along a line known as the seventh arc, to the west of Western Australia.

They came to this conclusion by looking at the plane's last transmission on March 8, 2014, and then examining a large search area in the Indian Ocean, which was partially based on how far the plane could have glided.

The plane crashed somewhere along this line, known as the seventh arc. ( Supplied )

That position was at latitude 39 to 36 degrees south along the seventh arc, but nothing turned up in the hunt.

Last December, they thought an area that spanned 25,000 kilometres at latitude 32 to 36 degrees south, pictured below outlined in orange, was the right place to look.

Within that new region outlined in December, they have since narrowed it down greatly to a relatively small area near 35 degrees south.

The most recent research by the CSIRO has strengthened scientists' belief this is where the plane may be found.

The yellow line on this map marks where 35 degrees south intersects the seventh arc (the black line). The purple area is the original search area, and the orange is the 25,000km search area determined in December.

Is there hope of finding MH370?

"We think we know quite precisely where the plane is," Dr David Griffin from the CSIRO told a national marine conference in Darwin.

He said while the physical search was suspended in January this year, the work had continued in Australian laboratories, modelling ocean drift.

What's ocean drift modelling?

It is a scientific method that involves looking at what the ocean currents were doing on the day of the crash, and matching it with where debris has and has not landed, such as the piece of wing, called the flaperon, which landed on Reunion Island off the eastern coast of Africa.

It can direct scientists towards where the plane might have landed based on where the debris turned up.

Dr Griffin also said specific damage to an outer flap of the plane that washed up in Tanzania, showed it was not deployed, which in turn suggested the pilot was not in control and had a hard landing.

That is relevant because it means the plane would have had a shorter maximum glide distance, so therefore its impact would be closer to the seventh arc than first assumed when the original search area was designed.

The observation that no debris had washed up on the West Australian coast was also an important clue.

It means the ocean current must have been flowing in a particular direction — and not towards Australia, which Dr Griffin says leads back to only one place on the arc where the plane had crashed. Again, that is 35 degrees south.

"There's a strong current crossing across the seventh arc at [latitude] 35 degrees south, so we think the plane crashed into that current going to the north-west," Dr Griffin said.

"That explains why debris didn't arrive in Australia."

The scientists used satellite technology to precisely calculate the height of the sea level, down to the centimetre, which is a key to figuring out where the ocean was flowing on March 8, 2014.

A detailed map of the sea level can reveal where the ocean currents are and what speed they're going.

"And so that's the basis of how we know this current was flowing across the seventh arc at this time," Dr Griffin said.

Where to from here?

The physical search of the ocean floor and aerial surveillance has already cost $180 million. It was suspended until authorities said they needed "credible evidence" to resume searching.

The CSIRO has handed over this work to the appropriate authorities, who will decide whether to resume the search for MH370.

Since April, when the last update on the flaperon modelling was reported, the scientists have said they are more confident than ever they are on the money.

"Since then we've been further scrutinising that work, and being a bit bolder to realise that 'yes, the answer has been there since December', that 'yes, actually there really is only a very small number of places which are consistent with all the evidence'."