Workplace regulator WorkSafe has issued 11 written notices to fast food companies, asking them to ensure physical distancing and hygiene requirements under alert level three.
It comes after Unite Union claimed some fast food restaurants were breaching the distancing requirements with every single drive through order, saying customers were being served by employees within two metres and without effective barriers between them.
WorkSafe representatives visited 80 fast food outlets this week unannounced to review Covid-19 compliance, including McDonald's, KFC, Burger King, Wendy's, Burger Fuel and Carl's Jr.
The 11 written notices issued were related to inappropriate physical distancing of staff and people picking up orders, and other measures not being adhered to, for example sanitising eftpos machines.
WorkSafe declined to say which companies had been issued notices. It said the health and safety concerns raised must be addressed within a certain time frame.
Unite Union national secretary Gerard Hehir said the one-metre rule between workers was being breached thousands of times a day in some fast food outlets.
"Of course this is happening inside closed restaurants so we don't see photos in the media," Hehir said.
"Workers are not allowed to have their phones with them while working and can be threatened with disciplinary action if they do. Workers have told us they are scared of repercussions if they use their phones to gather evidence.
"However, there are cameras in those stores recording 24/7 and Unite wants WorkSafe Inspectors to use them to monitor and enforce the social distancing requirements inside stores."
Under the Health and Safety at Work Act the companies have a legal obligation to keep their employees safe, he said.
McDonald's spokesperson Simon Kenny said "the number one priority in reopening our restaurants" was staff and customer safety.
"We developed our plan to operate under alert level 3 conditions in consultation with official government agencies and the advice provided publicly. Our operating plans and risk assessment were reviewed and had third party guidance," Kenny said.
"Staff also use our PeopleSafe health and safety system to report any incidents, concerns or ideas."
He said stores have acted on suggestions for improvements.
"Further enhancements to service procedures have been implemented since reopening as we analyse, listen, learn and act.
"This week there have been more changes with managing payments, and how food is handed to customers in drive through, or if a car is parked.
"We also have a staff member to oversee physical distancing, sanitation and hygiene, with hourly and per shift checklists, spot checks and liaising with staff to get real time feedback."
Burger King and KFC have been contacted for comment.