Thousands of unionized truck drivers across the country staged a one-day strike on Monday, demanding the parliament pass a bill that would improve their working conditions.

The members of a truckers' union affiliated with the Korea Confederation of Trade Unions, the more militant of the nation's two umbrella unions, also held rallies in the union's 15 regional offices.

"Since the National Assembly has yet to approve a cargo-related bill proposed in 2012, some 380,000 cargo transportation workers'

livelihoods are under threat," Park Won-ho, deputy chief of the union's Busan regional office, said during a rally held in the nation's largest port city. "We're ready to go on a general strike if the parliament does not approve the bill even after this one-day strike."

The bill calls for a fare increase, ensuring basic labor rights and protecting ownership of truckers and their license plates, allowing more trucks to benefit from toll discounts, and tightening surveillance on cargo overloading.

The union initially planned to stage the one-day strike in April but delayed the plan due to the Sewol ferry disaster that claimed more than 300 lives. (Yonhap)