The Official Cash Rate is expected to rise this year, although forecasters say predicting when is tricky.

Inflation was stronger in the December quarter than expected, at 3.1 percent.

Infometrics Principal Economist Brad Olsen is picking a hike in November - with an outside possibility of one in May. 

He says other signs in the market signal a possible increase. 

"Actual bank rates for longer-term mortgages have already started to increase a touch this year."

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