Lawmakers under the parliamentary environment and labor committee hold a meeting on Thursday. (Yonhap)

A parliamentary committee unilaterally passed a pro-labor bill Monday that aims to limit companies from making claims for damages against legitimate labor union disputes.

Lawmakers affiliated with the main opposition Democratic Party and other progressive parties passed the revision to the Trade Union and Labor Relations Adjustment Act, nicknamed the yellow envelop bill, during a plenary session of the parliamentary environment and labor committee.

In protest, the ruling People Power Party left the meeting.

Last year, the National Assembly passed the bill but President Yoon Suk Yeol vetoed it given strong opposition from business lobbies and the ruling party.

The controversy dates back to May 2009, when unionized workers of SsangYong Motor Co. staged a strike to oppose layoffs. Five years later, the Supreme Court declared the strike illegal and ordered the workers to pay 4.7 billion won ($3.6 million) in compensation to the company and the state.

Civic activists then delivered yellow envelopes with donations to support the SsangYong workers, raising the need to amend the trade union law in favor of striking workers. The revision has since been called the yellow envelope bill.