"Our mortgage market share is marginally down for September versus the previous period, reflecting the bank's decision to put the focus on quality rather than market share," he says.

"This decision was signalled clearly by (managing director) Cameron Clyne in the November profit announcement when he stated that the BNZ would not chase market share at any cost, but would focus on profitable growth and maintaining sound asset quality."

The spokesman says that the additional reporting requirements of the Basel ll agreement, which will apply from the March 2008 quarter, have led to BNZ improving its reporting systems. The current reporting framework is based on the Basel l international agreement signed in 1988.

BNZ's latest general disclosure document showed that its loans secured by residential mortgages rose $1.81 billion to $24.32 billion in the three months ended September 30.

That quarterly increase was significantly higher than the BNZ has recorded in previous quarters - in the December 2006 quarter its increase was only $540 million while in the March 2007 quarter, the increase was as much as $857 million.

By comparison, the much larger ANZ/National Bank's loans secured by residential mortgages rose $1.5 billion in the three months ended September, taking its total to $49.51 billion.