Singapore's Maritime Port Authority (MPA) has banned tanker owner Panoil Petroleum from operating bunker vessels in the port.

Its licence has been revoked with effect from 14 August, MPA said in a statement, according to Bloomberg.

MPA added that checks conducted between January and March revealed unauthorised alterations were made on five Panoil tankers.

The port authority temporarily suspended the licences of the five ships in March after it found irregularities with piping fixtures, an MPA spokeswoman told Reuters at the time.