The green onion, a beloved vegetable among South Koreans, has unexpectedly become the latest political weapon for opposition parties to attack President Yoon Suk Yeol and the ruling party.

It all started with Yoon's visit to a hypermarket in southern Seoul on March 18, just before he rolled out measures to tame food prices in the country. There, Yoon noticed that a bundle of green onions weighing 1 kilogram was selling for 875 won ($0.65), significantly lower than the usual price of between 3,000 won and 4,000 won. Yoon said the price, about 70 percent cheaper than the market price, was "reasonable."

But the event instantly fueled criticism that the grocery store had reduced its prices just before Yoon's visit, with some opponents calling it a staged act.

Some other opposition party members also criticized Yoon for being ignorant of the livelihood of ordinary citizens suffering from the steep inflation of essential costs.

What fueled the controversy was a media interview of Lee Soo-jung, the ruling People Power Party's candidate running for the Suwon-D electoral district, when she claimed that Yoon was referring to the price of "a single green onion," not the entire bundle. Lee later apologized for her misunderstanding.

The green onion controversy even led to a decision by election authorities to prohibit voters from entering polling stations if they were carrying certain items last week.

On Saturday, the National Election Commission released a statement that voters will be advised to leave "any object that could affect voter decisions" outside of the polling station. It also said some "specific objects" could be used to "express political views."

However, the NEC implied that staff would not stop voters from entering polling stations "unless the voters express their political view" with the object.

The statement was an apparent follow-up of the NEC's decision not to permit any voters from carrying scallions inside the polling station, during the two-day early voting session for the nation's legislative election on Friday and Saturday.

Opposition party leaders are taking advantage of the situation, claiming the election authorities are "influenced by the repressive administration."

Democratic Party of Korea Chair Rep. Lee Jae-myung on Saturday said during his visit to Yongin, Gyeonggi Province, that the Yoon administration is trying to "block green onions" inside polling stations, just like its bodyguards "covered the mouths" of protesters critical of Yoon. Lee showed up at the scene while holding a helmet with a green onion attached to it.

"Why can't we bring green onions into the polling station?" Lee said. "The NEC should stand in the neutral territory, but it is instead being careful in watching out for the repressive regime."

Another Yoon dissident Cho Kuk, who founded his party in March, posted on social media Sunday that he "had scallions in mind" when casting his vote in Busan on Friday, ending his post calling for a "scallion revolution." Cho was formerly the justice minister who was probed by Yoon when he was the prosecutor general. He was given a two-year prison term at an appeals court for his involvement in an academic fraud case involving his children.