Parliamentary officials said lawmakers decided not to hold sessions on Thursday and Friday to avoid unnecessary petrol use, days after authorities closed schools and some state offices for the same reason.
Energy minister Kanchana Wijesekera said a gasoline shipment that was due Thursday had been delayed and urged motorists to cut down on travel.
"Only limited amounts of petrol will be distributed to pumping stations today and tomorrow," he told reporters in Colombo, with motorists already waiting in line for days to top up their tanks.
Prime Minister Ranil Wickremesinghe said Wednesday that the nation's economy had reached the point of "complete collapse".
"We are now facing a far more serious situation beyond the mere shortages of fuel, gas, electricity and food," Wickremesinghe told lawmakers.
Sri Lanka defaulted on its $51 billion foreign debt in April and is in talks with the International Monetary Fund for a bailout which could take months.