The data showed electronic card spending lifted 1.1 per cent in August, above economists' predictions of a 0.5 per cent lift and after falling 0.1 per cent in July. RBNZ cut its official cash rate 50 basis points to 1 per cent early last month.
Westpac's chief currency strategist in Sydney, Robert Rennie, says poor business confidence in Australia also helped boost the New Zealand dollar.
National Australia Bank's index of business conditions fell 2 points to +1 in August, extending a slide from July. The survey's volatile measure of business confidence also declined, easing 3 points to +1.
Both measures were "well below" long-run averages, NAB said, adding it would review its outlook for Australian interest rates on Wednesday. NAB currently expects just one more rate cut from the Reserve Bank of Australia later this year, to 0.75 per cent.
Rennie says the market is relatively quiet ahead of key central bank decisions in Europe on Thursday and in the United States next week.
The European Central bank's decisions will be closely watched with Germany's economy threatening to go into recession.
Rennie says Westpac is expecting the ECB will cut its deposit rate by 10 basis points – it's first rate cut since 2016. That will take the deposit rate to minus 0.5 per cent from minus 0.4 per cent.
The ECB will also either reinstitute its asset purchase programme, or announce a commitment to do so. The programme is a form of quantitative easing – another way of saying money printing.
Rennie says Westpac is expecting that programme to be about 40 billion euro a month.
The market will also be looking for any measures the ECB decides to take to help banks by easing the pain of negative interest rates, a practice known as "tiering" or reducing the proportion of banks' excess liquidity subject to the deposit rate.
The Federal Reserve is also expected to cut rates next week, although the Fed funds rate is still well into positive territory at 2-2.25 per cent currently.
The kiwi was trading at 93.77 Australian cents from 93.59, at 52.11 British pence from 52.03, at 58.21 euro cents from 58.14, at 69.06 yen from 68.87 and at 4.5756 Chinese yuan from 4.5760.
The two-year swap rate edged up to a bid price of 0.9757 per cent from 0.9425 yesterday. Ten-year swaps climbed to 1.3250 per cent from 1.2500.
