Australia’s most powerful central banker is warning inflation will stay elevated as an escalation of the Middle East conflict makes another rate hike more likely during a housing market downturn.

A day after the US Federal Reserve raised interest rates for the first time in three years, Reserve Bank Governor Michele Bullock told MPs that widespread expectations of more interest rate rises in Australia were likely to be weighing down house prices, along with Labor’s controversial Budget taxes.

The futures market is now regarding a hike by Melbourne Cup day as an 82 per cent chance, that would take the cash rate to a 15-year high of 4.6 per cent and add $120 to monthly repayments on an average, new mortgage.

“We normally would expect, as we said, a response to interest rate rises and not just actual interest rate rises, expectations of interest rate rises,” she told the House of Representatives economics committee in Canberra on Friday in response to a question from Liberal MP Cameron Caldwell.

“If you look what was happening to the housing market, it had already started to ease at the end of last year and that was partly, I think, reflecting the fact that there are expectations building that interest rate rises were in the future.

“We do expect that. How much is due to tax changes and how much is due to interest rates and how much is just due to households being concerned about, worried about the conflict in the Middle East and what it might mean for other things is very hard to dissect.”

Sydney property prices peaked in February, during the month of the RBA’s first of three rate hikes this year, and have since plunged by 7.1 per cent since the US and Israel launched strikes on Iran, Cotality data showed.

Previously strong housing markets are now going backwards with Perth prices shedding 3.2 per cent since April while Brisbane prices have dived by 2.7 per cent since May when Labor delivered its fifth Budget since coming to power.

Crude oil prices this week hit $US105 a barrel for the first time since early May after an Iran-backed militia group fired drones on Saudi Arabia’s East-West pipeline connecting the Persian Gulf with the Red Sea as an alternative to the blockaded Strait of Hormuz.

“Higher oil prices have increased inflation directly through their impact on petrol prices but it’s also had an indirect impact as many firms have passed input cost pressure arising from elevated fuel prices through to the prices of other goods and services,” Ms Bullock said.

“Because of these capacity pressures and the Middle East conflict, inflation is likely to remain elevated for some time.”

The effects appeared to be worse than initially expected in late February, during the start of the Iran war, with basic unleaded petrol now typically selling for more than $2.30 a litre.

“Now we’ve got this extra impetus from a prolonged Middle East conflict,” she said.

“That is putting pressure on prices in Australia to the extent that businesses thought that maybe it would be short-lived, and they could perhaps wait and see whether they would pass cost increases through.

“Now, they’re seeing a prolonged period. I think there’s much more of an inclination to think that we need to pass through these cost increases because it’s going to be much more persistent.”

During the hearing in Canberra, Treasurer Jim Chalmers said the Reserve Bank’s three interest rate rises so far this year were hurting borrowers.

“It is already clear that the interest rate rises in the system are putting a lot of pressure on people with a mortgage,” he told reporters in Brisbane on Friday.

“We do understand that people are under pressure, that’s why we’re rolling out cost of living help and tax cuts.”

High government spending is also adding to inflation with the Reserve Bank expecting public demand to grow by 3.1 per cent this financial year, or more than double the 1.5 per cent economic growth pace.

“That’s government spending and government investment for all levels of government so, that’s direct spending in the economy on services, infrastructure projects, what have you,” the RBA’s chief economist Sarah Hunter told the hearing.

“It doesn’t include transfer to households, that would be social security payments and things like that, they get counted elsewhere.”

Ms Bullock added that excess government spending was adding to total demand for goods and services.

“Aggregate demand is made up of public and private and anything that adds to aggregate demand and keeps it above supply is contributing to that excess demand - it doesn’t matter whether it’s private or public,” she said.

“It is not my job to tell the Government, any governments, how they choose to spend their money.”

Inflation eased marginally in July to 3.5 per cent but it remained above the Reserve Bank’s 2-3 per cent target for the 12th straight month and financial markets are expecting at least another interest rate rise by November 3, following the release of more comprehensive September quarter inflation data.

“At the moment, we think demand is above supply and we think that low productivity growth means the economy can’t grow very fast,” Ms Bullock said.

Higher interest rates have also pushed Australian Government bond yields to the highest level since 2011, which adds to Commonwealth debt interest payments, which Treasury tips will cost $32 billion this financial year.

“Our yields have moved up as other yields have moved up overseas and reflecting very similar factors - inflation, expected interest rates, the neutral interest rate, I think it’s not unexpected that everything is moving up together,” Ms Bullock said.

The RBA meets again on September 28 and 29 with the next decision occurring a day before the Australian Bureau of Statistics releases August inflation data.

The Reserve Bank isn’t expecting headline or underlying inflation to fall back within its band until mid-2027, by which time the consumer price index would have been above target for almost two years.