The trust owns 241ha of formerly milled land south of the Waipoua Sanctuary which is home to great trees such as Tane Mahuta and Te Matua Ngahere.
The acquisition was the first expansion to the Waipoua Forest in 150 years. The aim is to reclaim bush in which the diverse native species of kauri country can again thrive, and to ensure that in 1000 years trees the size of Tane Mahuta will be standing in the Millennium Forest, Ms Davis said.
''These forests provided homes for our beloved native fauna like kiwi and kereru which are also sadly under threat from invasive pests.
''The Waipoua Forest Trust is working alongside other local organisations to reverse this trend and re-establish as much of these fantastic ecosystems as possible.''
The kauri tree is facing its greatest threat since 99 per cent of the giant trees were felled in the timber rush from the mid 1800s to early 1900s.
''We are in danger of losing the remainder to kauri dieback disease,'' Ms Davis said.
Recently the trust upgraded its vehicle wash-down station to prevent the spread of kauri dieback. Staff and volunteers also collect up all materials, tools and vehicles and water blast them.
''The disease can spread with a spore in soil the size of a pinhead so it is essential that as well as cleaning our shoes, we wash down all vehicles before they enter and leave the forest,'' Ms Davis said.