While household loan debt had increased $16b from March 2020, the value of household assets has risen $417b, it said.
"Rising asset prices, including property prices, have meant that the total net worth of New Zealand households has increased strongly in recent quarters," national accounts senior manager Paul Pascoe said in a statement.
The rising value of household owner-occupied property contributed $172b of the rise in household assets since March last year.
Financial assets, which include shares, businesses, equity in rental properties, bank deposits, and retirement savings owned by households, contributed $245b to the increase in household assets since March last year, exceeding the rise from the owner-occupied property.
When combining rental properties with owner-occupied property, the increases in the values of residential property accounted for about 54 per cent of the household asset increase for the March 2021 year, Stats NZ said.
Meanwhile, a new series of data out from Stats NZ showed that savings by New Zealanders in the March quarter fell to its lowest level in two years after rising sharply in 2020.
Increases in household spending outpaced income growth, leading to a decline in household savings from the elevated levels that prevailed throughout 2020.
"Household spending increased in the March 2021 quarter, after having been kept in check for much of 2020 by Covid-19 restrictions," Pascoe said.
"Government support measures including the wage subsidy meant that households were able to maintain relatively stable levels of disposable income through 2020," he said.
"This was despite the COVID-19 restrictions, which constrained household spending. As a result, we saw high levels of household saving throughout 2020."
With households spending more in the March 2021 quarter, the household saving ratio had fallen back from the quite high levels experienced through 2020.
The ratio, which compares saving with net disposable income, was 0.4 per cent in the March 2021 quarter, down from 3.2 per cent in the December 2020 quarter.
Net disposable income represents the money that households have available to spend on goods and services after accounting for things like taxes.
In the March 2021 quarter, net disposable income rose 3.1 per cent, but a 6.1 per cent increase in household expenditure reduced household saving to $0.2 billion in the quarter, Stats NZ said.