Still a long way to go for Gunns: Brown

There is a long way to go before the Gunns pulp mill is built, despite it securing the approval of the federal government, the Australian Greens say.

Environment Minister Tony Burke on Thursday gave the final tick to the controversial mill to be built at Bell Bay in northern Tasmania, some three and a half years after it first secured conditional approval.

Mr Burke delayed the decision after Gunns itself sought tougher environmental controls last week. Greens leader Bob Brown said Gunns still needed to convince the local community of the mill's credentials.

"The minister for the environment has ticked off from his small box as far as the Gunns pulp mill is concerned, but that's not a social licence," Senator Brown said. "That's not a tick-off from the people of the Tamar Valley, it's not a tick-off from the Greens, and it won't be. "It is a long way before that pulp mill starts its job of polluting as prescribed in that location."

Mr Burke approved separate modules dealing with effluent trigger levels, land clearing and marine monitoring.

Other conditions related to response strategies that will kick in if and when the mill fails to meet different requirements. Discharge of effluent was one of the most contentious issues with the mill.

"It will now be a condition of the project as a whole that the discharge can only occur through what's known as elemental chlorine-free light technology," Mr Burke told reporters in Canberra.

The technology is a form of bleaching.

"This is a much tougher environmental condition.

"It is one that has been demanded by environmental groups, it is something which Gunns have been saying they were willing to do, they will now have to do it as a condition of the development."

But Greens Senator Christine Milne said the new standards weren't as stringent as those Gunns had initially promised.

"Gunns said it would build a totally chlorine-free mill," Senator Milne told reporters in Hobart.

"That was its proposal and it has failed by its very own mouth." Senator Brown said the Greens would fight against "any dollars" from the federal government going to the building of the pulp mill.

But Tasmanian Deputy Premier Bryan Green said the mill presented tremendous opportunities for the state.

"This will be by far one of the cleanest and technologically advanced pulp mills in the world using only plantation stock," he said.

"The government is hopeful the mill goes ahead because of the enormous economic benefits to Tasmania and the opportunity to build a new forest industry around our world class plantation resource."