Bus drivers of privately owned SouthLink have agreed to hold a 24-hour work stoppage over unsettled pay and conditions claims either Tuesday or Wednesday after the Holy Week.
The bus transport line operates the services in Adelaide's north and south and in the Adelaide Hills.
"This is a matter between the union and the bus company. The state government is not a party to the issue," Industrial Relations Minister John Rau said in a statement on Monday.
"However, we are concerned about the impact this further escalation will have on commuters."
The South Australian government is particularly agitated over the matter especially if the transport union chooses Wednesday, it would the "significant" visit of the Duke and Duchess of Cambridge to Adelaide.
Organizers expect 50,000 people to Elizabeth and line its suburb streets in anticipation for the royal tour. Elizabeth unfortunately is serviced by SouthLink buses.
"That's just the way it goes, if that's the day that we've picked so be it. If they get tied up in that well we're sorry but that's the most important thing for us," Union official Ian Gonsalves said.
"The operators have had enough, they're sick and tired of them not listening to them," Gonsalves added. "This is their only option."
SouthLink buses management has offered a 3 percent annual pay rise. It has also promised to render action to address safety concerns. All that remains on the negotiations table is the matter on rostering.
"It's more for conditions than pay and that's the big sticking block at the moment," Gonsalves said.
Contingency plans are currently being drawn up to minimize the impact of the strike on commuters, Transport Minister Stephen Mullighan said.
He added the government will hire non-union drivers to cover the SouthLink bus services.