A Labour MP has begun walking the Hillary Trail in the Waitakere Ranges to draw attention to a disease threat to kauri trees.
The party's associate environment spokesperson, Phil Twyford, says over the past five years local authorities, iwi and government agencies have done research on kauri dieback disease costing nearly $6 million.
But Mr Twyford says spending by the Ministry of Primary Industries, which has funded most of the research, is due to end next year.
He says scientists have told him the kauri could become extinct within decades if no way is found to combat the disease.
A spokesperson for Primary Industries Minister David Carter says the ministry is considering taking a different approach, but will continue to fund management of the disease.