Why Australian Petrol Price Cycles Have Stretched From Weekly to Monthly and What It Costs You

Why Australian Petrol Price Cycles Have Stretched From Weekly to Monthly and What It Costs You

Something fundamental has changed about buying petrol in Australia, and unless you've been paying close attention, you've probably been caught out by it. Remember when you could reliably fill up on a Tuesday and know you were getting a decent price? Those days are largely gone for most of the country.

The numbers tell a stark story. In 2010, Brisbane motorists had an opportunity to buy cheap petrol roughly every week. By 2024, that dropped to about nine times across the entire year. The average cycle in Brisbane stretched to 42 days. And in one extraordinary period that ended in mid 2025, the city endured a 95 day price cycle, more than double what anyone would consider normal.

What exactly is a price cycle, and why should you care?

If you've ever watched petrol prices, you've seen the pattern. Prices creep down over days or weeks, hit a low point where savvy motorists rush to fill up, then spike overnight, sometimes by 30 cents a litre or more. The whole thing then repeats.

This happens in all five of Australia's largest cities: Sydney, Melbourne, Brisbane, Adelaide and Perth. It's the result of competition between retailers, specifically how discount chains like Costco and Metro Petroleum force the majors to follow their prices down, before everyone resets to higher prices and starts again.

What's changed is how long this takes to play out.

The great stretching

According to ACCC analysis, the average cycle duration in Sydney, Melbourne and Brisbane increased from around four weeks in 2018 to approximately seven weeks by 2023. In Sydney, cycles that once lasted 19 days at their shortest now regularly stretch beyond 50.

The NRMA has been tracking this closely, and their research paints a concerning picture. Their analysis of 51 price cycles in Sydney since January 2019 found motorists exposed to some of the highest gross margins, the gap between wholesale and retail price, on record. During the final cycle of 2023, covering Christmas and New Year, the average gross margin hit 21.5 cents per litre.

To put that in perspective, in 2019 the daily margin exceeded 30 cents on just five occasions across the entire year.

Brisbane wears it worst

While Sydney and Melbourne have seen their cycles stretch, Brisbane has copped the roughest deal. The ACCC's December quarter fuel report revealed Brisbane retailers charged motorists the highest margins of any capital city at 24.1 cents per litre profit, more than 4 cents higher than Sydney and nearly 6 cents above Melbourne.

The RACQ has been vocal about what they're calling evidence of market failure. That record 95 day cycle they documented saw high margin days (over 25 cents per litre) on 39 separate days, while only three days across that entire period were considered cheap.

"A typical fuel price cycle would usually last about six weeks. We have never seen a cycle last three months," RACQ Economist Dr Ian Jeffreys noted.

Queensland Transport Minister Brent Mickelberg has joined calls for an ACCC investigation, and there's growing pressure for some form of price regulation.

What's driving the change?

Ask the industry and they'll point to broader cost of living pressures. Mark McKenzie, CEO of the Australasian Convenience and Petroleum Marketers Association, argues the longer cycles reflect market adjustments rather than manipulation.

The NRMA sees it differently, arguing prices are being "artificially inflated" through extended high price periods. Their data shows Brisbane's margins in 2024 ran almost three times higher than Perth's.

The truth likely sits somewhere in between. Petrol price cycles aren't the result of some coordinated conspiracy. They're an emergent pattern from competitive dynamics. But the stretching of these cycles does mean motorists spend more time exposed to higher prices, with fewer windows to catch the bottom.

External factors play a role too. That 95 day Brisbane cycle was influenced by Tropical Cyclone Alfred pausing price movements for a week, and global oil price fluctuations from US tariff uncertainty and OPEC production decisions.

The Perth exception

Here's where things get interesting. Perth remains the cheapest capital city for fuel, averaging 181.4 cents per litre compared to Brisbane's 195 cents and Sydney's 191.1 cents in recent NRMA surveys.

Perth's cycle also remains relatively short and predictable, typically weekly, with prices bottoming on Tuesday or Wednesday and peaking by Thursday or Friday. This is partly due to Western Australia's FuelWatch scheme, which requires retailers to lock in next day prices by 2pm each afternoon.

The NRMA calculates that Perth's cheaper fuel could save the average Australian family around $426 annually compared to families paying Brisbane prices.

The cost to your wallet

ACCC calculations show that in 2023, a Sydney motorist who timed their fill ups to catch the cycle bottom could have saved approximately $407 across the year. But that figure assumes you can actually identify and catch those low points.

With cycles now stretching to seven or eight weeks in Sydney and Melbourne, and even longer in Brisbane, the window to buy cheap has shrunk dramatically. Miss it by a few days and you might wait two months for another opportunity.

For a typical family filling a 60 litre tank weekly, the difference between catching the bottom versus the peak of a cycle can easily be $15 to $20 per fill. Over a year, that compounds.

What happens next?

The Federal Government extended the ACCC's fuel monitoring powers for another five years from January 2026, suggesting this isn't an issue Canberra plans to stop watching. But monitoring isn't the same as acting.

The RACQ is pushing for Queensland to adopt a five cent per litre daily price cap, designed to prevent the sharp overnight spikes that characterise the start of each new cycle. The idea is to "shorten and flatten" the cycle, giving motorists more consistent pricing.

Whether that happens remains to be seen. The industry argues regulation would reduce competition and ultimately hurt consumers. Consumer advocates counter that the current system already isn't working for families.

How to beat the cycle (or at least not get beaten by it)

Until the regulatory picture changes, your best defence is information. Real time fuel price apps exist for every Australian state and territory, mandated by law. The ACCC updates buying tips at least three times weekly on their website.

Some practical strategies that actually work:

Watch for the pattern, not the day. The old "fill up Tuesday" advice is outdated. In Sydney and Melbourne especially, cycles don't follow weekly patterns anymore. Instead, watch for prices that have been declining for several weeks.

Use lock in features. Several fuel apps let you lock in current prices for up to a week, buying you flexibility to physically fill up when convenient rather than when prices happen to be low.

Consider location. Prices vary significantly even within the same city. Parramatta and Sydney's western suburbs consistently undercut inner city servos. Same pattern holds in Melbourne where suburbs like Epping and Dandenong often run 5 to 8 cents cheaper than closer to the CBD.

Don't chase long weekends. Retailers time peaks around public holidays. If you're planning a road trip, fill up well before the holiday period begins.

The bigger picture

Australia's petrol price cycles are unique in the developed world. No other country has quite the same pattern of slow declines and sharp spikes, repeated endlessly across major cities. Some economists argue this proves our market is working, with aggressive discounters forcing prices down. Others say it proves exactly the opposite, that consumers are being systematically disadvantaged by pricing opacity.

What's clear is that the cycles have changed, and not in motorists' favour. You're now exposed to higher prices for longer periods, with fewer opportunities to catch a bargain. Understanding this shift is the first step to not being caught out by it.

The NRMA noted that price cycles appeared to wane toward the end of 2025, which may signal some relief ahead. But after years of stretching cycles and record margins, Australian motorists can be forgiven for remaining sceptical.

Keep watching this space. The fuel industry rarely makes headlines until something dramatic happens, but the quiet changes over the past five years have already cost Australian families hundreds of dollars. That's worth paying attention to.