At least $10 million in funding over the next decade is needed to combat the wilding conifer problem on Northern Southland's Mid Dome and bring it down to manageable levels.
Mid Dome Wilding Trees Charitable Trust chairwoman Ali Ballantine Timms said a written request had been made to all government departments and the minister with responsibilities relating to wilding conifer control, asking for a substantial increase in funding for phase 2 of the national wilding control programme in the 2019-20 budget.
So far, $7.6 million has been invested since the late 1990s to control more than 60,000ha of affected land.
She said the trust estimates at least $10 million will be needed to eliminate high altitude seed sources and to have the area fully cleared and handed back to landowners to manage by 2030.
Ballantine Timms said that not all conifers would be eliminated with that investment, but that the problem would be at a ''very manageable level''.
Conifer seeds can stay in the ground for two to three years before a sapling emerges.