ASB on Tuesday afternoon undercut mortgage rate cuts by the country's biggest bank, ANZ New Zealand.
ANZ, which also owns the National Bank, cut its one, two and three-year fixed-mortgage rates in the morning.
Those cuts ranged from half a percentage point for the shorter-term rates to a tenth of a percentage point for the three-year rate.
ASB undercut the ANZ on its 18-month, two- and three-year fixed-mortgage rates.
Both banks are offering a fixed rate of 5.95% for one-year mortgages.
Both cited lower funding costs as a result of speculation the Reserve Bank will cut the official cash rate next Thursday in response to the Christchurch quake.
