Unionized bus drivers at some 230 bus operators nationwide have been voting to decide whether to go on strike to demand follow-up measures to a reduction in legal working hours.

The drivers are asking for higher wages to make up for decreased earnings that will result from the implementation of a 52-hour workweek system in July.

Under that system, firms with 300 or more employees have to reduce weekly working hours from 68 to 52.

According to the Korean Automobile and Transport Workers' Federation, labor unions of bus operators in Busan, Ulsan and South Chungcheong Province voted on Wednesday to go on a strike with approval rates of around 90 percent. In Gwangju, 95 percent of unionists approved the strike in a vote tallied earlier on Thursday. 

Almost 90 percent of union workers in Seoul also approved the strike on Thursday. 

If labor and management fail to come to an agreement, the unionized bus drivers are legally permitted to go on strike from next Wednesday.