The ruling Democratic Party (DP) has threatened to conduct a parliamentary investigation into the finance ministry for underestimating this year's surplus tax revenue, ratcheting up pressure on the government to endorse the DP presidential nominee's push to provide universal COVID-19 relief funds.

DP floor leader Rep. Yun Ho-jung said during a YTN radio interview Tuesday that this year's excess tax revenue is expected to reach 50 trillion won ($42.2 billion), which is 19 trillion won more than the ministry's estimate of 31 trillion won in July.

Yun said the extra 19 trillion won can be used to finance a package of COVID-19 relief measures, including universal handouts, and blasted the ministry for the accounting error.

"(The ministry) must be held accountable for this," he said. "I believe they should apologize to the people."

When asked if the discrepancy appeared intentional, Yun said, "If it was intentional, I think we should even conduct a parliamentary investigation, for example."

DP presidential nominee Lee Jae-myung has proposed giving relief handouts of 300,000-500,000 won to all people despite the government's repeated opposition over concerns of fiscal soundness.

The party recently revised the amount downward to 200,000-250,000 won in consideration of the estimated tax revenue surplus and has pushed to give the handouts in January.

The ministry released a statement Tuesday afternoon acknowledging the mistake but denying it was deliberate.

"An intentional underestimation of the tax revenue is unthinkable and we clearly state that we did not do so," it said, adding that the extra 19 trillion won in surplus tax revenue will first be used to compensate small merchants for their COVID-19 business losses and then be transferred to next year's tax revenue.

The public discord between the DP and the government is expected to intensify as parliamentary deliberations on the government's 2022 budget proposal get under way. (Yonhap)