This takes place when the petrol is pumped to the Kolonnawa storage terminal, according to them.
The CPC has 1,235 filling stations countrywide, while Lanka IOC has 212 filling stations.
The Kolonnawa storage terminal has a stockpile of 11,000 metric tons of petrol, reports say.
A ship carrying a petrol order is due to arrive at Colombo port at 12.30 am on November 09.
It will take until the 11th to test the samples, unload the consignment and to distribute it, a CPC spokesman told Sri Lanka Mirror.
However, there still are long queues at filling stations in the country.
Pictures: Suneth Gallage