Japan's three biggest banks are all raising their rates for fixed-interest mortgages from August after watching long-term interest rates heading upwards.

Banks set their own fixed mortgage rates based on factors such as the long-term interest rate level. MUFG Bank raised its prime rate on 10-year fixed-rate home loans by 0.09 points to 0.78 percent. Sumitomo Mitsui Banking hiked its rate 0.1 point to 0.89 percent. Mizuho Bank has raised the rate by 0.05 points to 1.2 percent.

All three banks made their decisions before the Bank of Japan announced last Friday it would allow a further rise in long-term interest rates and introduced greater flexibility in its yield-curve control policy.

Since that announcement, the yield on the benchmark 10-year Japanese government bond has been rising sharply. That rise is expected to be reflected in fixed mortgage rates from September.

Meanwhile, the big banks have decided not to change their adjustable mortgage rates. Those move in tandem with short-term interest rates.