A shortage of jet fuel at Melbourne Airport has started to ease with supply resuming to some terminals and airlines reporting no delays.

A fuel shortage on Friday sparked concerns of diversions and flight delays following the delivery of a substandard shipment of imported aviation fuel.

The ABC was told that less than 2 million litres of aviation fuel was available at the country's second busiest airport.

An A380 can require more than 300,000 litres of fuel for a long-haul flight.

ExxonMobil, the representative of the fuel suppliers, said the issue had arisen following disruptions in recent weeks to jet fuel deliveries from a number of terminals across Melbourne.

"While the issue is not yet resolved, supply has started to resume from some of the impacted terminals which may help bolster supply at the airport and soon alleviate the need for customer allocations," the company said in a statement.

Airlines make contingency plans to avoid delays

Airlines Qantas and Virgin made contingency plans and said so far there had been no delays.

Two Qantas international flights were diverted to Sydney to refuel after airlines were rationed to half of the amount of fuel they would normally use.

Virgin said it was flying as normal and that most domestic flights were arriving in Melbourne with extra fuel on board.

"The fuel supply issues at Melbourne Airport have so far had no impact on Virgin Australia's operations in or out of Melbourne," the company said in a statement.

"We do encourage our guests to check the flight status page on the Virgin Australia website for the most up-to-date information."

Storage capacity 'needs to be improved'

Victorian Energy Minister Lily D'Ambrosio said the shortage highlighted the need for Melbourne to match other airports like Sydney, in terms of storage capacity.

"Melbourne Airport is a world-class international airport but for far too long, Melbourne Airport has not had sufficient jet fuel storage to be able to meet the growing needs of the flights that are coming in and out of Melbourne," she said.

"We cannot continue this level of uncertainty where there is potentially from moment to moment insufficient jet fuel supply because of storage issues at Melbourne Airport."

A decade ago seven fuel refineries operated in Australia but now there are only two in Victoria and imports from Asia are needed to meet the demand.