Rising home prices and loan interest rates have made houses the least affordable in over four years, the latest data showed Monday.

According to the Korea Housing-Finance, the Korea-housing affordability index rose to 58.9 in the first three months of the year, up 0.4 percentage point from the previous quarter. This is the highest since the fourth quarter of 2012, when the index stood at 59.9.

K-HAI reflects the burden of loan repayment for homebuyers with median income who purchase average-priced housing. Higher numbers indicate greater burden, with an index of 100 meaning that 100 percent of the income goes to paying back the principal of home-backed loans.

The index was the highest for Seoul, up 1.2 percentage points to 103.6. For the southern island of Jeju, it rose 6.2 percentage points to 85.1.

A separate measurement, the Korea-housing opportunity index, also indicated falling affordability of homes. This index counts the number of available homes for buyers with average income. A fall in the index means that the number of affordable homes is decreasing.

K-HOI had reached 64.8 in 2012 but fell to 63.3 in 2013, to 62.5 in 2014 and to 61.7 in 2015. It further declined to 60.4 last year.

Real estate market watchers said the phenomenon has mostly to do with rising prices of homes and interest rates on mortgages. 

The Korea Appraisal Board said housing prices rose 0.21 percent on-month in June, a much bigger jump than 0.14 percent in May. The pace of the rise was especially high for Seoul, increasing 0.66 percent in June, and for Sejong, a city south of the capital and home to many government ministries and agencies, whose numbers marked a 1.67 percent increase in June.

The interest rate on home-backed loans as of March this year was 3.21 percent, up 0.55 percentage point from August last year. This has forced households with home loans to use more than 30 percent of their earnings to pay back the principal. (Yonhap)