The trap can automatically kill up to 24 rats, stoats or mice before the gas canister needs replacing. Image / Supplied
Greater Wellington senior biosecurity officer Paul Horton said the chocolate comes in a little pack which slowly squeezes out the lure paste over about six months.
But it is not like the Whittakers and Cadbury treats we would buy for ourselves.
"I haven't gone ahead and tasted it personally, but it doesn't smell like it.
"It's made with these animals in mind so it's not like a normal chocolate but it still smells pretty good and it's attractive to rats, they like sweet things."
Horton said chocolate had been a go-to for trappers for quite a long time.
"Rats go for chocolate, they'll go for pretty much anything actually. They're really opportunistic.
"That's why they're such a successful species and why they live in so many different environments because they just adapt and they eat what's around.
"Chocolate, if they smell that around and it's accessible - which it always will be for a rat - they can get into pretty much anything. They'll chew through a pack or a wooden door to be able to get some food and if it's chocolate, the motivation's pretty high."
The trial has been running since 2015 on Te Ahumairangi and Horton said it was proving successful.
The chocolate lure drops to the ground to attract the rats. Photo / Supplied
"This is a learning opportunity, it's an area where we can innovate and trial rat control using these traps and this lure pretty much because the possum numbers - there's none there.
"It means that we can reduce the number of bait stations in the area and use these traps to try and keep a hold of the rat population as much as a bait station network would. That's just gonna be an ongoing learning process for us."
The A24 Goodnature traps are used across the country with the chocolate lures, but this is a specific trial site where only the traps are used.
Horton said in other areas a range of tools are deployed to control pest numbers.
