ANZ Bank and Kiwibank will reveal the extent of their riskier mortgage lending in their quarterly accounts this week.
Radio New Zealand's business editor reports that accounts lodged by the Bank of New Zealand and ASB last weekshowed their lending to people with skinny deposits is still growing.
ANZ is the biggest home-lending bank in New Zealand and Kiwibank is Government-owned.
However, Westpac's account shows it has been reducing such lending for several quarters.
BNZ's mortgage book grew by a net $455 million in the three months ended March.
It's lending to people with deposits of less than 20% rose to 14.8% in March compared with 14% a year ago.
But while BNZ's riskier mortgage lending is growing, it is still considerably smaller than that of the other three major banks: ASB was 22.2% of its mortgage book at the end of March while Westpac's was 23.6%.
ANZ was just over 24% at the end of December while Kiwibank's then was 19.3%.
Both ANZ and Kiwibank's riskier mortgage lending has been growing in recent quarters.
But an ANZ promotion announced on Friday, a one-year fixed rate mortgage at a 4.95% annual interest rate, is specifically targeting those with deposits of more than 20%, as have Kiwibank promotions.