The bank’s December quarter disclosure document shows its mortgage book grew $1.152 billion to $34.9 billion during the quarter.

Using the Reserve Bank’s figures for lending on housing by the registered banks, that means the bank claimed 31% of new lending in the quarter and its market share slipped to 35.09% from 35.24%.

However, the pace of growth in the bank’s mortgage book picked up from $746 million in the September quarter.

Earlier this month, Bank of New Zealand, which has yet to release its December quarter disclosure document, claimed to have won 26% of all new home loans written in December while ASB Bank, which is also yet to release its December quarter document, claimed 30% of new mortgage lending in December.

Chief executive Sir John Anderson told analysts the bank’s net interest margin fell 2 basis points to 2.76% as the impact of the mortgage rate war was offset by 2%, or $839 million, growth in deposits.

Anderson says the price war was "really quite silly. Obviously, everyone lost out on that situation in New Zealand."

ANZ/National didn’t match the BNZ and ASB’s rates. "We still had 40 basis points return. As I understand it, the ASB and BNZ were making nothing."

While margins have now returned to more normal levels, Anderson still expects the trend for margins to be squeezed to continue over the medium to longer term.

Growth in the mortgage book sourced from mortgage brokers remained steady with ANZ/National’s share of brokers’ business remaining about the same level as brokers’ market share.

"Brokers aren’t stupid. They like to deal with people who deliver for them," Anderson says. ANZ/National’s real growth is coming from its own branch network, he says.