Westpac and Kiwibank won the market share war in the mortgage market during the March quarter, both boosting their shares slightly, figures show.
Westpac has just about 20 percent of the market, while Kiwibank has just over 7 percent.
The other three major banks all lost a small amount of market share during the three months.
Overall mortgage lending by registered banks shrank to just over $2.1 billion in the three months ended March, compared with $2.75 billion in the three months ended December last year.
All five of the major banks shrank their lending to people with less than a 20 percent deposit, known as high loan-to-value (LVR) lending, in the latest quarter.
Westpac's mortgage book grew $584 million in the quarter, despite its high LVR lending shrinking by $219 million.
Kiwibank's overall book grew by $386 million, despite its lending to people with small deposits shrinking by $130 million.
The nation's largest bank, ANZ Bank, shrank its high LVR lending by $1.7 billion but still managed to grow its overall mortgage book by $631 million.
The National Bank of Australia-owned Bank of New Zealand showed the smallest overall increase, of $223 million, in its mortgage book but that was despite its high LVR lending shrinking by $377 million.
