Long queues at service stations have appeared as conflict in the Middle East cause a surge in fuel prices and raise concerns about supply, but an economist says the motivations behind the behaviour have shifted.
Tim Neal, who has researched panic-buying at scale, said the behaviour during the pandemic was primarily about future supply concerns from lockdown disruptions.
"With fuel prices, there are supply concerns especially when it comes to diesel," Dr Neal told AAP.
"But what initially started the panic-buying was a price motive. People are stocking up because you expect future price increases."
More than 500 service stations were without some kind of fuel on Thursday but more petrol and diesel was flowing to the regions, Energy Minister Chris Bowen told parliament.
"There are real shortages, particularly in regional areas, that need to be addressed," he said.
Oil prices have skyrocketed since the US and Israel launched attacks on Iran in late February.
Iran has in turn attacked regional energy infrastructure and effectively closed the Strait of Hormuz, forcing countries to respond to global fuel supply shortages.
National cabinet will meet to discuss the ongoing fuel crisis on Monday.
Sudden spikes in demand could quickly outstrip supply, leading to temporary outages, Dr Neal said.
But he said it was too early to determine whether shortages were driven more by supply disruptions or surging demand, but both factors were likely at play.
Efforts to curb panic-buying were often limited once it began, Dr Neal said, because the behaviour becomes self-reinforcing.
"All you need for panic-buying to be rational is to believe that other people are going to be panicking," he said.
Tougher penalties for price gouging passed parliament on Thursday afternoon.
Legislation doubling the maximum fine for false and misleading conduct or cartel behaviour to $100 million was given the green light by the Senate to deter petrol companies from profiting from the shortages.
"We're not immune from uncertainty and volatility in the global economy, but this action is all about protecting consumers and holding petrol suppliers and retailers to account," Treasurer Jim Chalmers said.
Mr Bowen has left the door open to measures aimed at driving down fuel demand, including encouraging people to work from home and increasing levels of ethanol in petrol.