Exploitation of migrant workers is a serious problem, but the state government's response goes too far, says Member for Hammond Adrian Pederick.
State Parliament last week debated extra regulation for the labour hire industry, which supplies workers on temporary visas to some of the Murraylands' largest businesses, including Thomas Foods International and Costa Adelaide Mushrooms.
Mr Pederick described the measures as "draconian".
"The Weatherill Labor government has refused to listen to the concerns of businesses and stakeholders," he said.
"The government's proposal, which will basically result in more paperwork and bureaucratic back-and-forth, could perversely drive labour hire companies over the border."
In Parliament, he spoke about the "massive contribution" migrant workers had made to Murray Bridge, including the many Chinese immigrants who had since become Australian citizens.
Member for Schubert Stephan Knoll estimated that "90 to 95 per cent" of labour hire companies did the right thing, and that the extra red tape would punish them unnecessarily.
"The only way that this bill, if it becomes law, is going to improve workplace conditions for those who work for labour hire companies is if it is enforced," he said.
"If enforcement is the answer ... enforce the current act."
The proposed laws made it through Parliament's House of Assembly last Tuesday.
On Thursday, debate began in the Legislative Council, where government MP Ian Hunter said the laws were needed to protect some of the most vulnerable people in the community from predatory business practices.
He said rogue operators were underpaying workers, failing to ensure safety standards and abusing worker visas.
A particular concern was "phoenixing", where people would avoid their legal obligations by winding up their companies and re-incorporating them under new names.
In 2016, an Australiasian Meat Industry Employees Union representative told The Standard such activities were happening in Murray Bridge; a Senate inquiry later that year also found evidence of wrongdoing in the region.
The government's proposal was inspired by an ABC Four Corners program in May 2015, which led to a state inquiry.
Debate will continue in Parliament.