Amid continuing inflation and ensuing efforts by monetary authorities to counter it by raising the key interest rate, a benchmark lending rate for mortgage loans has hit a near three-year high. 

According to the Korea Federation of Banks on Monday, the COFIX, or the cost of funds index, for outstanding loans climbed zero-point-12 percentage points from March to one-point-84 percent in April. 

It marks the highest level since May of 2019 when the index reached one-point-85 percent. 

COFIX is calculated based on the weighted average cost of funding information provided by eight domestic banks.

When the index climbs, the interest on COFIX-linked mortgage loans also goes up, raising the household debt burden.

For example, the lowest adjustable interest rate imposed on mortgage loans offered by KB Kookmin Bank will rise from three-point-42 percent to three-point-54 percent from Tuesday, while that of loans by Nonghyup will rise from three-point-17 to three-point-29 percent.