The number of new houses on the market has increased by nearly 50% in February, according to the latest survey.
Realestate.co.nz says the number of properties being listed rose to 15,129, up 47% from January.
However, sales volumes remain flat. At the current rate, it would take almost a year to clear the backlog of more than 54,000 houses listed for sale.
Chief executive Alister Helm says the surplus of housing could lead to lower prices in the coming months.