Deficit debt that must be repaid by the public is projected to reach the 1.3 trillion won range by 2030, exceeding this year's figure by more than 280 trillion won.

Due to the increase in national debt, interest expenses are also expected to rise, surpassing 50 trillion won per year.

According to the Ministry of Planning and Budget, the deficit debt in next year's budget proposal stands at 1,117.1 trillion won.

This is an increase of 91.9 trillion won compared to this year's supplementary budget (1,025.2 trillion won).

Deficit debt is projected to gradually increase to 1,192.4 trillion won in 2028 and 1,245.8 trillion won in 2029, reaching 1,312.3 trillion won by 2030.

Compared to this year's supplementary budget, this represents an increase of 287.1 trillion won over a four-year period.

Over the same period, financial debt will increase by 34.3 trillion won, from 387.6 trillion won to 421.9 trillion won.

The proportion of deficit debt in total national debt is projected to gradually increase from 72.6% based on this year's supplementary budget to 73.5% next year, 74.5% in 2028, and 75.1% in 2029, before expanding to 75.7% by 2030.

Conversely, the share of financial debt will decrease from 27.4% this year to 24.3% in 2030.

However, the scale and proportion of deficit debt have improved compared to the previous mid-term plan (the 2025–2029 National Fiscal Management Plan), which projected 1,248.1 trillion won (75.0%) for 2028 and 1,362.5 trillion won (76.2%) for 2029.

This is attributed to an increase in revenue driven by a large-scale tax boom stemming from the semiconductor super-cycle.

Deficit debt refers to debt in general accounts, net debt of local governments, national treasury obligation acts, and debt of accounts and funds aimed at settling and repaying liabilities.

Unlike financial debt, which can hold financial assets, deficit debt has no corresponding assets for the borrowed money, meaning it is strongly characterized by having to be repaid essentially through the public burden.

For this reason, the steeper increase in deficit debt compared to financial debt is generally interpreted as worsening not only the quantity but also the quality of the national debt.

The government has historically included deficit debt forecasts in its annual National Fiscal Management Plan or its attached document, the National Debt Management Plan, but did not disclose them in the document submitted this year.

An official from the Ministry of Planning explained regarding this, "As there is no fixed format for the National Debt Management Plan, the deficit debt portion was omitted while drafting it in a new format this year."

The explanation is that it was excluded during the process of reorganizing the content to fit changing circumstances.

Interest expenses resulting from the future increase of national debt are also projected to continue rising.

According to the 2026–2030 National Debt Management Plan, this year's national debt interest expenses amount to 36.5 trillion won, an increase of 4.8 trillion won from last year.

The figure will gradually increase to 42.8 trillion won next year, 45.4 trillion won in 2028, and 48.9 trillion won in 2029, ultimately surpassing 50 trillion won to reach 53.3 trillion won by 2030.

The ratio of national debt interest expenses to gross domestic product (GDP) will increase from 1.3% in 2026 to 1.5% in 2030.

The government stated, "We will manage the national debt interest expenses for 2030 at around 1.5% of GDP."

It added that when compared with the general government interest expenditure (D2) levels of advanced economies, South Korea stands at 1.3% this year and 1.5% next year, while the Organization for Economic Cooperation and Development (OECD) average is 2.0% this year and 2.1% next year.

Fiscal indicators such as the national debt-to-GDP ratio have improved as the economic size has grown following favorable growth rates.

The national debt-to-GDP ratio is projected to drop from 50.6% based on this year's supplementary budget to 48.3% next year, and then record 48.8% in 2029 and 49.0% in 2030.

The government explained, "This is a significant improvement of 9.0 percentage points compared to the 2029 national debt ratio (58.0%) projected in the previous mid-term plan (2025–2029)."

(Photo: Yonhap News)