The Community and Public Sector Union has asked Premier Will Hodgman for assurances that arbitration over a wage dispute with the government can be finalised by December.
Unions had been asked to provide feedback to the terms of reference spelled out by Mr Hodgman in June for an arbitration process to be handled by the Tasmanian Industrial Commission.
Acting Premier Jeremy Rockliff on Wednesday said it was expected an agreement on the path the process would take would be reached in the coming weeks.
In response to the terms of reference, CPSU state secretary Tom Lynch said arbitration would need to be prompt and efficient with a resolution by December 1.
He said there would need to be one arbitration covering all agreements to unions and the union would be prepared to eliminate the use of lawyers to spare taxpayer money.
Mr Lynch said there would need to be a clear agreement between parties that the outcome of arbitration would be incorporated into an industrial agreement.
"We are not prepared to agree to a process which does not deliver legally binding outcomes incorporated in a validly made industrial agreement," he said in a letter to Mr Hodgman.
Mr Lynch said the union did not agree that negotiations on conditions be suspended while the issue of wages was in arbitration.
"Some of the conditions about which we have been negotiating involve the safety of members and we will not agree to be silent about those matters," he said.
"Some of the members involved in this dispute are assaulted at work, including those emergency services, health and correctional employees."