South Korea's acting president, Han Duck-soo, is expected to test the waters by exercising the presidential veto powers delegated to him after President Yoon Suk Yeol's suspension on Saturday evening, despite repeated calls from the main opposition Democratic Party to abstain.

Tuesday's Cabinet meeting will likely be the last chance for the ruling conservative bloc to advise the acting president to use his power to send six opposition-sponsored bills back to the National Assembly for a revote. Han, as acting president, is the person who would preside over the Cabinet meeting, and who would approve a presidential veto.

This comes as the power vacuum in Asia's fourth-largest economy highlights uncertainties over the extent of the powers entrusted to the acting president, which are not stated clearly in the existing protocols or the Constitution. Also, the acting president is in a precarious position facing possible impeachment himself, having convened a critical Cabinet meeting in the hours just before Yoon's martial law decree.

The main opposition party demanded that Han sign their bills into law instead of vetoing them.

Rep. Kim Min-seok of the Democratic Party said Monday in a party supreme council meeting that the acting president "has no power to actively veto a bill or appoint any official."

Another lawmaker, Rep. Jeon Hyun-heui, said Han's use of presidential veto power "could be a cause for Han's impeachment," indicating a possible change in course from party leader Rep. Lee Jae-myung's recent statement that the opposition would no longer pursue the prime minister's impeachment.

Among the measures facing potential vetoes are two bills that would require the government to purchase surplus rice from farmers at a price above a certain level in order to stabilize the agricultural market.

Two other bills would prevent a rise in insurance premiums for farmers and require the government to compensate farmers in the event of a natural disaster.

The Democratic Party proposed a similar revision to the Grain Management Act in April 2023, but it was vetoed by Yoon. That was the first of the 25 bills Yoon vetoed during the first half of his five-year presidency, which, absent impeachment, would ordinarily have run until May 2027. The parliament did not have enough votes to override any of the 25 vetoes.

Moreover, the party also passed bills to revise the Act on Testimony and Appraisal Before the National Assembly and the National Assembly Act. These bills would give the National Assembly greater power to summon witnesses and would discourage the parliamentary committees from automatically submitting budget bills without having them fully examined.

The ruling bloc, including the ministries concerned and the ruling People Power Party, has consistently expressed disapproval of the bills. The ruling party floor leader Rep. Kweon Seong-dong on Friday said the bills were the outcome of "the opposition parties' parliamentary dictatorship."

The main opposition Democratic Party used its majority in the Assembly to pass all six of the bills in question on Nov. 28, and they were sent on Dec. 6 to the government to await signing.

Without a formal request by a president or equivalent official for a revote before Dec. 21, the bills will automatically become law.

There is a precedent in Korea for an acting president to exercise veto power.

Goh Kun, who was acting president when late former President Roh Moo-hyun was suspended due to an impeachment trial in 2004, vetoed two bills. They were a revision to the Amnesty Act meant to allow the National Assembly to express its opinion when a special amnesty is granted, and a revision of a special bill to restore the honor of civilians killed in the 1951 massacre in Geochang-gun, South Gyeongsang Province during the Korean War. Goh said these revisions could be deemed unconstitutional. Prime Minister Han was then a minister of government policy coordination who worked with Goh.

When asked by Rep. Lee Ki-heon of the Democratic Party on Wednesday whether Han would exercise his veto power as an acting president, Han answered he would "internally deliberate on the matter."

Even before the motion to impeach Yoon, accused of insurrection through his martial law declaration on Dec. 3, the veto was the go-to option for the head of state to keep the National Assembly's legislative power in check and deter a special counsel probe targeting him and his wife Kim Keon Hee.

Eyes are on whether Han will also exercise a veto in the coming weeks to strike down a special counsel investigation of Yoon's insurrection charges and Kim's multiple corruption allegations.