Formosa, Asia's top naphtha importer, operates three crackers that have a total capacity of 2.93 million tonnes per year (tpy) of ethylene.

"We have reduced the overall cracking rates by 5-10% this month in view of weak demand for polymers. Although China has resumed manufacturing activities, their inventories are seen high," said KY Lin.

Formosa, which operates one of Asia's 10 largest refineries, joins a host of petrochemical makers in Asia who has already taken a similar route of cutting runs to combat weak petrochemical margins.

The Taiwanese firm has also shut an 84,000 barrels per day (bpd) residue fluid catalytic cracker (RFCC) at its Mailiao refinery on March 2 instead of March 10 as originally planned.

"Oil products in general are not doing well, and it's not just gasoline. But we do not have plans on cutting refinery runs because of the scheduled maintenance that will last into April. We will review the situation again at a later date," Lin said.

It operates another RFCC unit of the same capacity where the run rates were raised to 90% from 80%.

One of the three crude distillation units (CDU) and one of the two 80,000 bpd sulphur remover units (RDS) will be shut on March 10 as planned.

The refinery has a nameplate capacity of 540,000 bpd.

It has three CDUs, each at 180,000 bpd.

(Reporting by Seng Li Peng; Editing by Maju Samuel)