U.S. mortgage applications increased 4.5 percent on a seasonally adjusted basis in the week ended Jan. 6, the Mortgage Bankers Association (MBA) said Wednesday.

Refinances were up 3.3 percent from the previous week, while puchases increased by 8.1 percent.

Refinances made up 80.8 percent of all applications, down from 81.9 percent -- the highest level in 2011 -- in the previous week. Adjustable rate mortgages increased to 5.4 percent of all applications, up from 4.7 percent in the previous week.

The four-week moving average for applications is down 0.53 percent, with purchases down 1.92 percent and refinances down 0.09 percent.

The average interest rate for 30-year fixed-rate mortgages of $417,500 or less was 4.11 percent, up from 4.07 percent in the previous week. The average interest rate for 30-year fixed-rate mortgages over $417,500 declined to 4.34 percent from 4.41 percent in the previous week.

FHA-backed 30-year fixed-rate mortgage rates were unchanged at 3.96 percent, while interest rates for 15-year fixed-rate mortgages increased to 3.40 percent from 3.37 percent.

The MBA's mortgage survey covers over 75 percent of the U.S. mortgage market