Rate rise pain all but certain after inflation shock

A 25 basis point hike will add about $90 in monthly repayments for people with a $600,000 mortgage. (Joel Carrett/AAP PHOTOS)

All four big banks are warning borrowers to brace for an interest rate hike after core inflation jumped above the Reserve Bank's forecasts.

Economists at Westpac and ANZ on Wednesday dropped their calls for the RBA to stay on hold in February after the central bank's preferred measure of inflation - the quarterly trimmed mean - came in at 0.9 per cent in December.