Another rise in interest rates in Australia is expected when the board of the Reserve Bank of Australia meets on Tuesday.
The RBA has already lifted the official cash rate five times since last October to 4.25% - well above New Zealand's rate of 2.5%.
Radio New Zealand's Sydney business correspondent says the prospect of a further move in May firmed last week when inflation data came in higher than expected.
The consumer price index almost doubled in the March quarter to 0.9%, taking the annual inflation rate to just below the top of the bank's target range of 2% - 3%.
Together with the wealth injection from Australia's boom commodity exports, the inflation data is seen by economic commentators as suggesting the RBA has more heavy lifting to do.
An official cash rate of 5% by year end is still expected.