The chemical arm of Malaysian state-owned oil corporation Petroliam Nasional plans to raise about $4bn in its initial share sale, people familiar with the matter said Tuesday, which would make it Southeast Asia's biggest offering ever.

Kuala Lumpur-based Petronas Chemicals Group, a unit of the company known as Petronas, is expected to be listed on the Malaysian stock exchange in November, according to a term sheet reviewed by Dow Jones Newswires.