CONSTRUCTION of ExxonMobil's largest owned and operated chemical plant in the world started on Jurong Island on Tuesday, as the petrochemical giant officially broke ground at a ceremony attended by Prime Minister Lee Hsien Loong.

When completed in 2011, the multi-billion dollar plant will be ExxonMobil's second chemical plant in Singapore, and will employ 400 permanent staff.

Together, the two plants will turn crude oil components in nearly two million tonnes of ethylene - an ingredient for making plastics - annually.

ExxonMobil will be using the Singapore chemical complex to launch its new cutting-edge elastomer, among a range of other products.

Called Vistamaxx, this specialty elastomer was developed in the United States and noted for being highly elastic and flexible, with uses ranging from clothing to medical equipment. .

Besides the Texas-based group, Shell is also in the midst of building a world-scale cracker on Jurong Island.

At the peak of construction, the ExxonMobil project will need up to 10,000 workers.

With two mega petrochemical projects taking place, PM Lee reassured investors such as ExxonMobil that the Government is committed to support the construction of new plants.

'In anticipation of the construction boom in the chemical industry, the Government has acted to head off potential supply constraints,' he said in his speech.

Measures include expanding the Jurong Island security checkpoint to cope with heavier traffic and making foreign-worker rules more flexible.

'We will do all we can to ensure that adequate resources to support the construction of new plants,' said PM Lee.