It's feeding time outside a police station in Dili, where three large saltwater crocodiles are kept as pets.

Key points: Researchers are collecting DNA from crocodiles in Timor-Leste

Researchers are collecting DNA from crocodiles in Timor-Leste They will cross-check those samples against a database of 700 crocodiles from northern Australia

They will cross-check those samples against a database of 700 crocodiles from northern Australia The research will allow them to work out the crocodiles' origins

As an officer dangles a chicken carcass into the enclosure, one of the reptiles lunges for its meal.

Watching on are a group of Darwin-based researchers, who have come to Timor-Leste on the hunt for crocodile DNA.

"We've got a four-metre-long spear that's got a little dart head on it," explains Professor Sam Banks from Charles Darwin University.

"It [gets] a five millimetre-long punch of skin that we can extract DNA from."

The scientists are trying to work out why crocodile attacks in Timor-Leste, also known as East Timor, have risen 20-fold over the past decade.

One theory is that Australian crocodiles might be to blame, and the only way to find out is through DNA.

"The crocodile population seems to have rapidly increased in East Timor," Professor Banks said.

"And it's been speculated that that's because [in Australia] we've had such a successful crocodile conservation and management program, that we are now effectively pumping out crocodile migrants that are going and settling in countries around Australia."

The idea of crocodiles travelling hundreds of kilometres across the ocean from the Top End to Timor-Leste might seem far fetched, but Professor Banks is less sceptical.

"There's been records of people working in the middle of the Timor Sea seeing crocodiles swimming past, so certainly [the theory is] plausible," he said.

Professor Sam Banks uses a four-metre-long spear to get a skin sample from a crocodile in Timor-Leste ( Supplied: Charles Darwin University )

The team plans to analyse the skin samples from Timor-Leste and cross-check them against a DNA database of 700 crocodiles from northern Australia.

"We can tell the birth place of any crocodile at a regional level at least," Northern Territory Government wildlife scientist Yusuke Fukuda said.

He and his colleagues have already used DNA to track the origins of crocodiles captured in Darwin Harbour.

"So far we have looked at 50 crocodiles in Darwin Harbour and most of them were from the rivers around the harbour, as you would expect, but some were from the Tiwi Islands and a few from rivers further away," he said.

It will still be several months before the research team is able to confirm whether Australian crocodiles are making their way to Timor-Leste.

Researchers are trying to work out if crocodiles from northern Australia are relocating to nearby countries. ( Supplied: Charles Darwin University )

"If we find out that that's the answer, then together we will have to start thinking about a regional strategy for managing animals like crocodiles," Professor Banks said.

"We like to think that animals have their borders stopping where our borders stop.

"But crocodiles don't necessarily behave the way we want them to, so this sort of (DNA) information can tell us how their populations work."