McLean said credit growth had slowed in the last six months despite variations in the housing market.
"We've responded by focusing our business on high quality deposits and lending, in the process helping more New Zealanders to save and own their own home."
Net loans at the bank rose 4 per cent to $92.1 billion while mortgages were up 4 per cent to $49.6b.
Lending to business grew at 5 per cent to $30.9b.
McLean said general conditions had remained favourable on the farm with milk prices increasing and meat prices stabilising at comparatively high levels.
"We continue to support growth in the agriculture sector, with lending rising by 6 per cent year-on-year and deposits increasing by 10 per cent over the same period," he said.
Funds under management in the Westpac KiwiSaver Scheme increased by 15 per cent year-on-year, to $6.4 billion as at 31 March 2019 and the average Westpac KiwiSaver scheme balance was now $16,149.
Total deposits also grew 4 per cent to $64.2 billion.
But the bank's net interest margin slipped one basis point to 2.23 per cent.
The bank's net operating income rose 6 per cent to $1.248b but its operating expenses also rose 3 per cent to $480m.
Its impairment expense fell from $38m to $14m
McLean said the low margin environment and evolving regulatory outlook would present challenges into the second half of the year.
"But we have confidence in the fundamentals of the economy, and our capability to execute in response to change."
McLean said Westpac was engaging constructively with the Financial Markets Authority and the Reserve Bank of New Zealand and had provided its response to the conduct and culture review by the end of March.
Parent company Westpac in Australia posted a 22 per cent fall in its cash half year profit to A$3.29b after it took a $896 million provision for customer remediation.