The unit's restart and petrochemical exports could hurt sentiment in naphtha markets as demand for the light distillate has struggled to recover this year, keeping refiners' margins under pressure.

The company's naphtha cracker in Pengerang, Johor, came back online early last week, three separate market sources said, after a month-long shutdown following a fire at the Pengerang Integrated Complex in end-October.

The cracker is currently running at an operating rate of 51% to 52%, one of the five sources said, although it was not immediately clear if products are meeting commercial specifications.

Ethylene is typically used as a raw material for further processing into petrochemicals within the complex.

PRefChem's naphtha cracker had been shut after damage occurred to interconnecting pipes at the Pengerang Integrated Complex due to a fire.

PRefChem, a joint venture between state-run Petronas and oil giant Saudi Aramco, has capacity to produce 3.4 million tonnes of ethylene, propylene, butadiene, benzene and methyl tert-butyl ether (MTBE) per year.

PRefChem and Petronas did not respond to requests for comments.

(Reporting by Mohi Narayan in New Delhi and Trixie Yap in Singapore; Editing by Kim Coghill)