There is a limit to what the Reserve Bank of Australia can do about a rising oil price, and its officials are increasingly candid about it. Interest rates cannot lower the cost of crude on world markets. What they can do is stop a one-off energy shock from spreading through the economy and settling into the general price level.

That distinction, drawn out by Assistant Governor (Economic) Sarah Hunter at the AFR Property Summit on 8 September 2026, is the key to understanding why a supply-driven price rise can keep Inflation higher for longer, and why the Bank still cares deeply about it even though Monetary Policy cannot address the cause directly.

With the cash rate at 4.35 per cent and inflation above target, the question of persistence, how long higher prices last, is now as important as the level itself.

What the RBA Said

Ms Hunter was explicit about the constraint. Using interest rates, she said, "we can't do anything about global oil prices". But she went on to describe what the Bank can influence: keeping domestic Demand and Supply in balance so that the initial shock does not trigger what economists call second-round effects, the indirect flow-through of higher energy costs into wages and other prices.

This is a supply-side shock. It originates outside Australia, in this case linked to the conflict in the Middle East, and it makes goods more expensive without any change in domestic demand. Monetary policy is a demand-management tool, which is why it is poorly suited to fixing the source of such a shock but well suited to containing its aftershocks.

The Bank's forecasts already build in a slow return to target. The August Statement on Monetary Policy did not expect inflation back to the middle of the 2 to 3 per cent band until around early 2028, with risks skewed to the upside. Deputy Governor Andrew Hauser has offered a slightly nearer horizon, saying inflation was "due to be back in target by the end of next year", or end-2027.

The Key Numbers

Fuel: +7.5% in July 2026; transport inflation up to 1.6%. Headline CPI: 3.5%; trimmed mean: 3.6%. Inflation midpoint target not expected until early 2028.

What Could Happen Next

Looking ahead, the length of the inflation episode will depend on two things: whether oil prices stay elevated, and whether domestic demand stays contained enough to stop the shock spreading.

Analysis of the Bank's framework suggests it will tolerate the direct, first-round effect of higher oil, treating it as largely outside its control, while remaining vigilant about the second-round effects it can influence. Ms Hunter said the Board may have to raise rates if inflation looks stronger than forecast, and described inflation as "top priority right now".

The target-return timeline is the anchor to watch. If the Bank starts to signal that early 2028, or Mr Hauser's end-2027, is slipping further away, that would be a sign the oil shock is proving more persistent than hoped, and could prompt a firmer policy response.

Conclusion

The Reserve Bank's message on oil is a lesson in the limits of monetary policy. Interest rates cannot bring down the world price of crude, but they can determine whether an energy shock fades quickly or lingers by embedding itself in wages and prices. With underlying inflation near 3.5 per cent and the return to target already pushed out towards early 2028, the Bank's focus is squarely on preventing the first-round hit to petrol from becoming a longer, broader inflation problem.