Environment groups have welcomed Environment Minister Tony Burke's decision to delay his decision on the pulp mill proposed for Tasmania's Tamar Valley, as the company behind the proposal, Gunns, is "seeking tougher environmental controls than were contained in the original application".

"The current proposal for the pulp mill, put forward by Gunns in 2007, would cause unacceptable damage to the environment, so it is appropriate that the Minister give the company longer to improve its proposal," said Lyndon Schneiders, Campaign Director for The Wilderness Society.

"Modern ‘world's best practice' pulp mills don't damage oceans and rivers, are supplied by wood from well managed plantations and gain a ‘social licence' through legitimate public consultation and transparent processes," said ACF executive director Don Henry.

"Environment groups have long campaigned on a number of major environmental impacts from the proposed mill, including the plan to source timber from native forests and potential risks to the marine environment, air pollution and water use," said Dr Phill Pullinger, Director of Environment Tasmania.

"We would certainly welcome any and every opportunity for stricter environmental controls to be placed on this proposal, but will have to reserve any judgement until we see the final decision," Dr Pullinger said.

"It is a important precedent for a company to seek tougher environmental controls for its own project, showing the company is heading in a positive direction," Lyndon Schneiders said.