Finance Minister Hong Nam-ki says global credit rating agencies are concerned about South Korea's quickly ballooning national debt. 

Answering lawmaker questions at a parliamentary hearing Tuesday, Hong said global appraisers are watching factors that are outside the scope of control, such as the supplementary budget currently under discussion at the National Assembly. 

He said global agencies in the past two to three years had optimistically assessed the government's efforts to manage the rapidly rising debt pile, but that such considerations appear to be reaching their limit.

Hong added it is difficult for the government to accept political parties' call to raise the extra budget to 35 trillion or 50 trillion won on concerns over inflation and the country's fiscal soundness.

He projected Korea's debt-to-GDP ratio could grow by two percentage points if the budget is increased to 35 trillion won from the government's proposal of 14 trillion won.