However, although its profits and assets dipped slightly in the September quarter.
Westpac's mortgage book grew by $682 million to $21.5 billion in the three months ended September and by $2.61 billion, or 13.8%, in the year ended September, its latest disclosure document shows.
Using Reserve Bank of New Zealand figures as a proxy for the market, that puts Westpac's share at 19.4%, unchanged since both the end of the June quarter and the end of the March quarter.
Westpac's market share did decline from 19.7% at the end of September 2004 and to 19.6% at the end of December, which is hardly surprising, given that the Bank of New Zealand's "Unbeatable" campaign was at its height late last year.
The central bank's figures show all lending on housing by registered banks grew $15.13 billion, or 15.8%, in the year ended September.
Westpac's net profit fell 4.6% to $145 million and total assets fell 1.4% to $45.05 billion.
Westpac spokesman Mark Watts says the slight decrease in both cases reflects the unwinding of structured finance transactions.
