Their daily ration of free Carlsburg is no small beer for employees of the Danish brewer who are now blocking deliveries to force management to turn the taps back on.

"Around 250 of our workers and drivers are on strike at our warehouse in Hoeje-Taastrup, just outside of Copenhagen," Carlsburg's communications director Jens Bekke said.

Angered over management cutting their daily free beer ration from three bottles to one, the warehouse employees went on strike on Wednesday and were joined by the drivers.

With Copenhagen deprived of deliveries from its top brewery for days, unions and the Danish employers' association have begun talks to resolve the dispute before city shops run dry.

"We have no idea how long the strike will last, but we hope that it will be as short as possible," said Bekke.