Ahead of tomorrow's OCR update, one expert is challenging the Reserve Bank to start cutting rates ASAP.

The Official Cash Rate is widely expected to stay at 5.5 percent, but Squirrel CEO David Cunningham believes the RBNZ should ease up.

Cunningham says monetary policy changes have a one to two-year lag before they flow through to the wider economy.

"What that means is- the Reserve Bank should always be looking a couple of years ahead in terms of what they do today and how they impact the future."

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