Three of Australia's big four banks say they will hold standard variable interest rates on mortgages steady after the Reserve Bank of Australia left the official cash rate at 3.75 per cent.

The central bank left the official interest rate unchanged today defying financial market expectations of another rate hike.

The National Australia Bank ,Westpac and the Commonwealth all say they will leave interest rates steady, ANZ has yet to announce its decision.

Standard variable rates on mortgages at the big four banks currently stand at 6.49 per cent at NAB, 6.61 per cent at CBA, 6.66 per cent for ANZ and 6.76 per cent at Westpac.