Extra protection is being put in place for New Zealand's modern-day dinosaur.

One of the world's oldest frogs the Archey's frog is getting world-first predator traps placed in their western King Country sanctuary.

The Department of Conservation says the native frogs are almost unchanged from their 150 million-year-old fossilised relatives and they want to ensure that the species continues.

This week 1300 self-resetting traps are being placed in 600ha of the Whareorino Forest in the western King Country.

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The Goodnature traps are aimed at controlling predators most of which are rats, Goodnature Technical Expert Sam Gibson said.

"The Archey's frog is also susceptible to diseases spread by humans, so the self-resetting nature of our traps will limit the interaction between humans and frogs, and hopefully reduce the risk of spreading disease."

They are the only predator trap in the world which self-resets up to 24 times before it has to be reset by a human. Traditional traps need to be checked every two weeks while the new traps need to be checked only every six months.

DOC's Native Frog Recovery Group leader Amanda Haigh said there were about 20,000-25,000 Archey's frogs thought to remain.

"It is very difficult to estimate frog numbers because we do not monitor all populations and frog numbers vary hugely across the landscape depending if the right habitat conditions are present,"

The Archey's frog has a number of distinctive features. It can't croak, they don't have eardrums, it has muscles for tail-wagging, despite not having a tail, and has an abnormally high number of vertebrae. It's young hatch as froglets so they don't have a tadpole stage. It is also New Zealand's smallest native frog, growing to 37 mm long.

The Coromandel Peninsula and Pureora are the two other places in the world that the Archey's frog are found.