The state's major projects legislation is expected to be altered by a slew of amendments, unnerving the government which has threatened to torpedo its own legislation.
Debate on the major projects bill started in the Legislative Council on Wednesday night and will continue on Thursday.
The biggest concern for the government is an amendment from Labor that will seek to prevent any developer who has made a political donation within a three-year period from having a project nominated by the Planning Minister.
Rumney Labor MLC Sarah Lovell said the State Growth Department had said while the move may be a variation on the policy intent of the bill, it would not impact on its operation.
"This is about providing confidence to the Tasmanian community that there is no undue influence over the assessment process for major projects," she said.
Nelson independent MLC Meg Webb said in many measures, the bill exhibited a high level of transparency and distance from political influence.
She said the necessity of the minister to play a part in the process still needed more scrutiny.
"That power to declare a project has to be recognised for what it is and that is significant," Ms Webb said
"It sits a political player in the process."
She said it should be a matter for the Tasmanian Planning Commission to make that decision.
Other amendments expected to be moved by members involve protection of some council decision-making powers and merit-based appeal rights for community members.
If this bill was amended in that way, we would not let it proceed.Roger Jaensch
Planning Minister Roger Jaensch said Labor from the outset had said it supported the bill.
"They voted for the major projects bill in the House of Assembly and we think it is now important for them to do what they said that they would do and support the major projects bill through the upper house without further amendment," he said.
"Donations rules don't belong in this debate on this bill.
"We believe it is discriminatory and potentially unconstitutional to ban a certain class of people from participating in a land use planning assessment process based on their political expression.
"If this bill was amended in that way, we would not let it proceed."
Mr Jaensch said any changes could derail the legislation and have serious implications for the state's planning system.
Greens planning spokeswoman Rosalie Woodruff said it was the job of upper house members to review and scrutinise legislation from the House of Assembly.
"It is not the job of this government to direct Parliament in how it does its duty."