Westpac is jacking up all of its variable home loan interest rates by 0.2 percentage points, a move it has blamed on rules forcing banks to hold larger loss-absorbing capital buffers.

The country's second biggest bank on Wednesday announced the change, which will increase headline owner-occupier rates to 5.68 per cent, and investor rates to 5.95 per cent.

The rate hike will take effect from November 20, and puts the spotlight on the home loan interest rates charged by the other banks, which tend to copy each other on mortgage rates. The changes apply only to Westpac-branded loans, not St George, Bank of Melbourne or BankSA.

Westpac said the changes were occurring because the bank was being forced to hold more capital, a buffer for absorbing losses.