The country's biggest bank, ANZ National, has slashed mortgage and deposit rates effective Wednesday.
Rates for one-year, two-year and three-year mortgages have been cut for the bank's ANZ and National brands.
The reductions range from half a percentage point for the shorter terms to a tenth of a percentage point for the three-year rate.
Deposit rates have been cut by between a quarter of a percentage point and .6 of a percentage point.
The bank says it is slashing rates in response to a fall in the cost of borrowing on local money markets over the past week.
Money market rates have fallen since last Tuesday's earthquake as speculation increases that the Reserve Bank will cut the cash rate.