The Tui Nature Reserve in Outer Pelorus Sound received the common geckos from nearby Conservation Department reserve Maud Island on Monday in what is the reserve's first gecko breeding programme.
Giant weta have also been bred at the reserve.
The geckos were freed into custom-built enclosures by the reserve's owners the Plaisier family and Ngati Kuia representative Raymond Smith, who blessed them first with a karakia.
It comes after almost two decades of hard work by the Plaisiers, and more recently the Tui Nature Reserve Wildlife Trust, to restore the once weed-ridden, barren peninsula to its natural state.
The arrival of the geckos, which was permitted by the department, marked a bigr milestone in that restoration, said family spokesperson Liam Plaisier, 14.
He hoped the 20 geckos, 12 females and eight males, would breed sufficiently in their custom-built enclosures to allow the release of some into the reserve.
How long this would take was unclear, as geckos are notoriously slow breeders and have only one or two young each breeding season, Liam said.
Common geckos already exist on the peninsula, but their numbers have been severely depleted by predators such as stoats, rats and mice.
Years of intensive pest control meant the peninsula was now mostly pest-free, which would be further helped by a predator-diverting fence to be built this year on the reserve's boundary.
The pest-free status, and success of the gecko release programme, would hopefully lead to the release of other species, Liam said.
Maud Island Conservation Department ranger Chris Birmingham said the geckos were taken from different sites on Maud Island to ensure genetic diversity.
The island's gecko population was so plentiful that removing 20 would not make an impact, which showed how well Maud Island was doing, Mr Birmingham said.
"It's pretty significant that we're able to transfer the geckos."
Addressing the Plaisiers and members of the trust before the geckos were released yesterday, Mr Smith said the reptiles held a special place in Maori mythology.
He hoped their presence in the reserve would increase its popularity so more people became aware and involved in the project.
"All of the people in this area, they need to see things like this."
MAIKE VAN DER HEIDE - Published in The Marlborough Express -