The Reserve Bank of Australia is tipped to lift the official interest rate to 1.85 per cent in August with a third 0.5 percentage point increase in the cash rate, in the most aggressive tightening cycle in almost 30 years.

After moving to an inflation-fighting footing in May, the RBA on Tuesday announced a second double “business as usual” 0.5 percentage point rate rise, taking the cash rate from 0.1 per cent to 1.35 per cent in three months.