The shop assistants' union in South Australia says making retail workers conduct mandatory COVID-19 vaccine checks will lead to abuse towards staff.
The Shop, Distributive and Allied Employees' Association says if retail workers are made responsible for conducting checks they will cop abuse from unwilling customers.
"Putting retail workers in charge of checking vaccine passports is like waving a red rag in front of a bull," union state secretary Josh Peak said.
"Most South Australians are willing to do the right thing, but we know there are the Covidiots out there that will seek to intentionally engage with or antagonise workers on this issue."
Mr Peak said he had written to Police Commissioner Grant Stevens this week to caution against any such direction in the retail sector without a plan.
He said any vaccine checks in the retail sector should be the responsibility of police or trained public health officials.
"Retail workers are not trained security guards. Many retail workers are young and vulnerable teenagers and shouldn't be held responsible for checking vaccine passports," Mr Peak said.
"It's important we do everything we can to lift vaccination rates, but it shouldn't come at the cost of workers' safety."