The Electrical Trade Union has reported that 230 casual electricians and mechanical fitters, who had been working at the Gangarri project near Wandoan, were fired by text message.
The workers were sacked as a result of a contractual disagreement between Indian multinational Sterling & Wilson and local firm Davis Contracting.
The Gangarri project is a 120 megawatt solar farm owned by Shell Australia which will generate enough energy to power 50,000 homes.
Shell, which is not involved in the labour dispute, expects the project to be completed by early 2021, but it's reportedly behind schedule.
There has been no official update by Shell yet.