Overseas volunteers such as Kathryn Grayston are the momentum behind a project to restore Lake Rotopounamu and Mt Pihanga to their former glory.

The Pacific Development and Conservation Trust recently gave a $50,000 boost to the project just south of Lake Taupo, run by the Tongariro Natural History Society and the Department of Conservation (DoC).

Travelling from England, Ms Grayston, 21, is dedicating six months to helping with the project.

Society director Sarah Gibb said she was thrilled with the grant.

"We can really make some progress with this. We have received several smaller grants in the past which we do appreciate, but with a lump sum like this we can really kickstart the project," she said.

The objective was to restore the Mt Pihanga/Lake Rotopounamu area to its original state.

Stoats, rats and weasels had devastated the bird population in the area.

DoC Turangi biodiversity technical support officer Nic Etheridge said the number of forest birds was declining rapidly.

"We are looking at a local extinction of the North Island robin within five years if nothing is done," she said.

A 500ha site around Lake Rotopounamu is the initial focus of the project.

There are 49 traps set around the lake that are cleared on a weekly basis by society volunteers. The grant will see 650 bait stations put in.

Ms Etheridge said she hoped the project would have the area relatively predator-free within five years.

"We hope in 10 years to extend that area to 4000ha, including Mt Pihanga."