* Company says unit being repaired after "smouldering"
* Says caused by minor leak at refinery near Melbourne (Recasts on repairs, adds detail)
MELBOURNE, Feb 16 (Reuters) - Viva Energy said it was repairing a minor leak on an unspecified unit at its 120,000 barrels-per-day Australian oil refinery on Thursday, after "smouldering" led to the unit being shut.
Local firefighters gave the all-clear just before 0600 GMT, about 2-1/2 hours after smoke from a column was detected.
"The smoulder was caused by a minor leak and repairs are underway," Viva Energy said in an emailed statement.
All other units at the plant were unaffected.
A media report said the affected unit was the plant's "cracker". The company had removed hydrocarbon feed from the unit earlier on Thursday while it investigated the problem. Viva declined to name the affected unit.
Viva, controlled by energy trader Vitol, runs the refinery in Geelong, near Melbourne, supplying about 10 percent of Australia's fuel. It is the exclusive licensee for Royal Dutch Shell's products in Australia.
Reporting by Sonali Paul; Editing by Christian Schmollinger and Joseph Radford