The bank's cash earnings in New Zealand grew by 68% to $210 million in the six months to March from $125 million in the previous corresponding period. That was after a $40 million impact from the earthquakes in Christchurch.
Core earnings, which Mr Frazis highlighted, grew by 13%.
The New Zealand business had operating income of $819 million in the period, up 9% on the pcp. Net loans were up 2% to $49.8 billion and deposits were up 5% to $31.6 billion.
Mr Frazis told the Otago Daily Times that the strong momentum Westpac continued to achieve in a subdued environment was further evidence the bank's customer-focused strategy introduced over the last 18 months was delivering good results.
"The New Zealand economy has experienced a more subdued recovery than Australia and the Christchurch earthquakes have added a further degree of caution to an already soft economy."
But the number of business loans under stress and the value of business loans in workout had declined, he said. The amount of 90-day delinquencies was higher in mortgages, but had declined in consumer lending.
The quality of its mortgage portfolio remained high, but mortgage delinquencies in New Zealand were higher than in Australia. Net mortgage write-offs improved.
The bank said a survey of its business customers in Christchurch showed that only 2% would be permanently affected by the earthquakes.
"The simplifying of processes to make things quicker and easier for our customers and the training of frontline staff, so local people are making local decisions, is resonating strongly with customers and the market."
Westpac had installed mobile branches in Christchurch to help customers with their banking needs.
Mr Frazis said the bank was still hiring bankers and intended to open new community branches. While growth across all sectors was strong, Westpac would like to be stronger in business and agribusiness lending.
"We are bullish on the New Zealand economy. Soft commodities are at all-time high and our key trading parties are doing well. That includes Asia, including China, and Australia.
"The last two years, people have been deleveraging and reducing debt. They are now able to invest for growth."
Mr Frazis also praised the Government for focusing on productivity and infrastructure developments which would help productivity.
The bank's result included an explanation of ongoing changes to the bank's structure in New Zealand at the behest of the Reserve Bank of New Zealand.
The bank has already moved from being a branch to a dual registration operating model and implementation of further changes agreed in 2009 are still being worked through.
In Australia, Westpac Banking Corporation increased first-half profit by 38% as impairment charges fell by half and on improved earnings across the business.
Net profit rose to $A3.961 billion ($NZ 5.38 billion) for the six months to March 31 from $2.875 billion a year earlier, Sydney-based Westpac said in a statement. Cash earnings increased 7% to $A3.168 billion.
Westpac said the net profit figure benefited from a one-off finalisation of tax consolidation to do with the St George merger, which was excluded from the cash earnings figure.
Westpac declared a tax-paid interim dividend of A76c per share, up from A65c a year earlier.
