Certificate of entitlement (COEs) quotas will be announced every three months, instead of six. The Land Transport Authority said this would make the supply of COEs - which motorists must bid for and secure before they can own a vehicle here - more responsive to the market. Previous quotas were decided every six months.

For the quota period February to April this year, there will be 717 COEs a month for cars up to 1,600cc and 130bhp. This is fewer than the previous monthly supply of 728 COEs. There will be 701 COEs for cars above 1,600cc and 130bhp, down from 746 previously.

For Open COEs, which can be used for any vehicle type but ends up mainly for bigger cars, the supply will shrink drastically from 522 to 382 a month. Motorcyclists will also feel the squeeze. There will be 719 certificates a month for them, down from 961.

The commercial vehicle COE supply is the only one that bucks the trend - it will grow from 514 to 524. In total, there will be 3,043 COEs - down from 3,471. Nevertheless, the LTA said the supply would have shrunk by another 5 per cent if it had applied the previous six-monthly formula. With the new supply, observers reckon premiums will remain firm for up to April.