The Reserve Bank is widely expected to deliver another 50 basis point hike to the Official Cash Rate at 2pm today as it moves to try to head off inflation in the economy.

That would be the fifth 50 basis point hike in a row - an unprecedented run - and take the OCR from 3 per cent to 3.5 per cent.

But with the global outlook darkening in the past few weeks, there are signs the central bank will have to hike further than its previously projected peak of 4 per cent.

Bank economists now forecast the OCR to peak next year at between 4.25 and 4.75 per cent.

Today, RBNZ Governor Adrian Orr just releases a short monetary Policy Review, rather than a full monetary policy statement, which means we won't get new economic forecasts.

So all eyes will be on the language and tone of the brief commentary that accompanies the rate decision.

Yesterday, the Reserve Bank of Australia surprised markets with a smaller than expected rate hike - 25 basis points as opposed to 50 basis points.

The Australian cash rate now sits at 2.60 per cent.

Local economists don't expect to see the RBNZ take this softer approach.

"We expect the RBNZ to repeat that the OCR will continue to rise at pace, and to signal a higher peak for this cycle," said Westpac chief economist Michael Gordon.

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"[It] may say that the committee anticipates a higher OCR path than what was
projected in the August statement."

Westpac last week shifted its forecast peak for the OCR to 4.5 per cent, following moves by ASB and ANZ predicting peaks of 4.25 and 4.75 per cent respectively.

"The key messages this time should remain similar to August's," said ASB chief economist Nick Tuffley.

The RBNZ should indicate it will keep lifting the OCR until it is "confident there is sufficient restraint" in place, and it is resolute in meeting its remit, he said.

The Herald will have full coverage of the RBNZ decision from 2pm including analysis and updates of any mortgage rate moves by the major banks.

The OCR was introduced in 1999. It was at its highest level, 8.25 per cent, from July 2007 to July 2008. At that time, oil prices were soaring and the Global Financial Crisis was underway.