Petrol prices in Australia could increase by 6-10% due to Middle East tensions affecting the Strait of Hormuz, with potential rises of approximately 30 cents per litre if oil increases by $30 per barrel. The price surge may impact inflation, as petroleum products comprise 12% of Australia's CPI basket, with indirect exposure affecting items like synthetic materials and airline tickets. The government's fuel excise of 51 cents per litre could be reduced as a policy response if elevated oil prices persist.