The vessel carried a cargo of 26,000 metric tonnes of petrol and 5,000 tonnes of diesel for LankaIOC, a unit Indian Oil Corporation which has a petroleum distribution operation in Sri Lanka.
A part of petrol consignment was discharged in Colombo and the balance at the Eastern port of Trincomalee.
The diesel which was found to be off specification in colour was denied permission for unloading following tests by a common user facility operator.
The cargo had to be returned to the supplier in Singapore, who had said the diesel was according to specifications when it was loaded.
A LankaIOC official said they had sought a court order to recover freight and other costs from the ship.