Drivers from the Goodman Fielder baking subsidiary Buttercup bread company in South Australia have gone on strike over a "knee-jerk" sacking of a plant worker who gave away five loaves of bread.

In a move organised by the Liquor, Hospitality and Miscellaneous Workers' Union, 45 drivers launched a 24-hour strike on Wednesday.

The union said that the company sacked the worker in question as a "knee-jerk" reaction, and that no warnings were given.

The strike left managers at the plant forced to rent taxi trucks in order to deliver the bread to local supermarkets in Adelaide.