Workers at Adelaide's Coca-Cola production factory have had their shifts cancelled and a meeting has been called for Wednesday morning leaving about 150 jobs in doubt, the union has said.

Staff have been told to attend a meeting at the Port Road business at 8:00am for an announcement, which will coincide with the release of the company's 2016 full-year financial results.

The union, United Voice, said it understood some casual workers at the plant were stood down today.

United Voice spokesperson Carolyn Smart said it had not been advised of any other job losses.

"We would be extremely disappointed if workers were advised of any job losses tomorrow, especially given the consultation clauses contained in their enterprise agreement," Ms Smart said.

"Workers have had no advance warning of any changes or closures. United Voice has not been consulted about any changes either.

"If it is the case, it is a sad reflection on multinational corporations and the distain they've shown for their workers."

The company has been contacted for comment.

The South Australian Government said it had also contacted the company to find out about tomorrow's meeting, but had not had a response.

It said it will make sure it provides whatever support is needed for workers.