The crisis continues at Wanganui's Bushy Park, where rats have been found inside a predator fence erected to protect endangered birds.
More than nine rats have now been caught inside the 100ha forest sanctuary. Bushy Park Trust chairwoman Liz Tennet said it was still unclear how long rats had been inside the fence, or how they got there.
A Conservation Department (DoC) plan is being implemented by up to 30 volunteers this weekend. They will be checking the fence for holes once again, setting and checking more than 100 rat traps and putting poison in tracking tunnels.
They have also cut back branches on both sides of the fence, to make sure rats can't get in by climbing trees.
There's no evidence so far that the rats are harming endangered tieke (saddleback), hihi (stitchbird) and toutouwai (North Island robin) or the other birds in the sanctuary.