The Reserve Bank will keep official interest rates unchanged until next year, and then only increase borrowing costs slowly, because record mortgage debt has created a "housing powder keg," Deloitte Access Economics says.

In a report that also says slowing in the housing market could drag on growth, the consultancy highlights how sensitive many households are to interest rate changes, which will limit sharp increases in the cash rate, now at 1.5 per cent.

Financial markets have in recent weeks questioned whether the Reserve Bank of Australia may follow the lead of foreign central banks such as Canada's and start to signal a return to more normal interest rates.

However, Access said the RBA would only increase the cash rate cautiously in 2018, in line with a forecast pick-up in inflation. It said a "genuine tightening of financial conditions" would not commence until 2019, because the RBA would be wary of squeezing the budgets of mortgage holders.