Cement workers are worried they may not receive redundancy payments if Holcim Australia sells its Tasmanian plants.
Holcim Australia is part of a global building materials company.
It is closing its cement businesses in Hobart, Huonville and Launceston this month, citing the building industry downturn.
In all, the company's closing 30 of its Australian plants.
Tasmanian workers say 13 full time staff were told a fortnight ago they were being made redundant and would be paid out.
The workers say they were later told the company may sell the plants, and the new owner would be responsible for paying their entitlements if they were not re-employed.
Workers have sought legal advice and raised concerns with Fair Work Australia about how Holcim has handled the process.
A company spokesman says it's complying with its legal obligations and is keeping employees informed.