An economist is tipping another big Official Cash Rate rise.

It's expected the Reserve Bank will hike the Official Cash Rate an unprecedented 75 basis points tomorrow.

Independent economist Cameron Bagrie says whether it's 50 or 75 basis points - it's still a large move.

He says in the context of the past 12 months, it'll be the most aggressive increase in the Official Cash Rate ever seen.

LISTEN ABOVE

• The Reserve Bank is set to hike rates up next week
• Reserve Bank predicted to hike OCR by 50 basis points
• More mortgage pain – Reserve Bank delivers double rate hike
• Reserve Bank lifts OCR by 50 basis points to 2.5 per cent