The Environmental Defence Society says it does not understand why it's taking so long for the Gisborne District Council to investigate whether forestry companies operating in Tolaga Bay have breached their resource consent conditions.
An estimated one million tonnes of forest debris were swept onto properties and roads during two flood events in a week, earlier this month, but the question of who will pay for the clean up and compensation was still up in the air.
The Gisborne District Council said an investigation into possible breaches could take up to six months.
Environmental Defence Society chief executive Gary Taylor said after such devastating damage, someone must be held responsible.
"Prosecutions simply have to follow otherwise people can avoid their environmental responsibilities with impunity.
"Someone is responsible for that damage and the council needs to rattle its dags and get on and prosecute them," Mr Taylor said.
He hoped to bring up the issue at a meeting with the Department of Conservation today, which the minister Eugenie Sage may also attend.
The urgent need for changes to forestry practices in light of the damage caused by slash in Tolaga Bay and on the West Coast recently has increased with the government's one billion trees programme, Mr Taylor said.
"What we need with the billion tree programme is revisiting how we do forestry so that we don't make a seriously bad problem worse by inappropriate practices," he said.
The Forestry Minister Shane Jones had previously said the programme was about planting the "right tree in the right place" now that the new National Environmental Standards for Plantation Forestry were in effect.
That was the right objective but a detailed plan was needed, Mr Taylor said.
"We want to see exactly what that means ... so what trees are being planted on the East Coast of the North Island in that very instable, steep erosion-prone land. What trees are being planted on DOC stewardship land? We need to see this mapped," he said.