The slight gain in mortgage-backed securities came as the government began encouraging people to switch to lower and fixed-rate mortgage loans from the second half of last year, FSS officials said.

"Mortgage loans sales were on the rise in the second half of 2016, based on which MBS (mortgage-backed securities) issuance has continuously increased," the statement said.

Mortgage securitizations by the state-run housing financing company stood at 10.4 trillion won in the fourth quarter last year, 9.8 trillion won in the third quarter of last year and 5.9 trillion won in the second quarter of last year.

Household debt, which stood at 1,344 trillion won at the end of last year, has been cited as a major hurdle facing South Korea's economy as a mountain of debt threatens to choke off consumer spending.

During the first quarter of this year, asset-backed securities worth 13.9 trillion won were issued, up 3.2 percent on year, the FSS data showed.

Credit card firms boosted their issuance of asset-backed securities during the quarter, while installment finance companies' issuance fell significantly.

"With rising interest rates and improved overseas issuance conditions, credit card companies expanded ABS (asset-backed securities) issuance abroad," the statement said. (Yonhap)