A monthly report on housing sales published by the Realestate.co.nz website, shows the current sales rate would take 32.4 weeks to clear the backlog of houses on the market.
That's 10% less than in previous month and a 31% drop on the same month last year.
Website chief executive Alistair Helm says the continued high demand for property has also led to yet another record high for average asking prices - they reached almost 430,000 in March, up from 427,000 in February.
"The high number of sales in February 2012 has squeezed inventory to a point not seen since February 2008," says Mr Helm. Compared with the same time last year, no regions are at or below the long term average times taken for accumulated stock to sell.
Nationally, average asking prices reached a high of $429,865 in March, up from the high of $426,575 in February, partly driven by record average asking prices in Canterbury ($383,395) and the Waikato ($380,315).
Auckland has an average asking price of $559,369, in seasonally-adjusted terms.
Mr Helm says numbers of new listings coming onto the market are in line with forecasts but might not be sufficient in some areas if demand continues to grow.