A bill to dole out cash-equivalent vouchers universally to every South Korean citizen gained parliamentary approval at the opposition-controlled National Assembly on Friday, about four months after opposition leader Rep. Lee Jae-myung proposed the scheme.

The 13 trillion-won ($9.4 billion) bill, designed to offer 250,000 won cash coupons to the entire 50 million population across the country, won 186 votes from 187 lawmakers present at the National Assembly. In South Korea's political landscape, seven opposition parties including the main opposition Democratic Party of Korea, occupy 191 seats in the 300-member parliament.

The ruling conservative People Power Party boycotted the move and walked out of the plenary session.

Before the passage, People Power Party lawmakers took turns engaging in a filibuster to delay the legislative process. The filibuster was short-lived, as the opposition parties asked National Assembly Speaker Rep. Woo Won-shik to stop the filibuster within 24 hours after it started. Before his term as the Assembly Speaker began in June, Woo won the April election as the Democratic Party lawmaker.

In the meantime, four-term lawmaker of the Democratic Party Rep. Seo Young-kyo urged the Assembly to pass the universal payout bill at a press conference Friday, saying it would help "stimulate consumption and boost the local economy."

The scheme was part of a campaign pledge by former Democratic chair Lee ahead of the April general election, which led to the ruling bloc's crushing defeat.

The bill's fate, however, is uncertain as President Yoon Suk Yeol's office deems the bill as not only unconstitutional but also lacking bipartisan consensus.

A senior official of the presidential office told reporters Friday that the opposition parties' move "breaches the (Yoon) administration's rights for budget planning, and thereby breaches the principle of the separation of powers."

All eyes are on whether Yoon would exercise his veto power again concerning the bill that the ruling party labeled as being "populist." Yoon has already vetoed 15 bills sponsored by the opposition parties, as he is relying on the veto power to stop the opposition parties from railroading the bills into law.