As a result, dozens of forecourts have run out of fuel, with several towns and cities in the Algarve having already run dry, with unleaded fuel shortages the most common.
Elsewhere in the country, diesel was the first to run dry.
The government has meanwhile confirmed that a civil requisition order should cover stocks at 40 percent of fuel stations, with priority being given to major urban centres such as Lisbon and Porto.
Officials have also said the military could be called in to assist in replenishing fuel stocks.
Airports in Faro and Lisbon have already been forced to use emergency fuel reserves for departing planes, though the civil requesition is expected to cover the demand.
Some airlines have also reportedly resorted to diverting to Spain to refuel.
Truck drivers are striking due to demands they have made for the past decade falling on deaf ears, including an increase in their wages.
Unions are warning that even with the civil requesition, it will take some time to replenish fuel stocks, and will be further delayed by the upcoming Easter long weekend and the greater demand due to holiday travel.