Supermarket chain FairPrice yesterday capped the amount of certain essential items customers can buy, including toilet paper, poultry, instant noodles and rice.

Each customer can buy up to four units of paper products - toilet paper, facial tissues and kitchen towels - as well as two units of instant noodles or pasta, two bags of rice, $30 worth of vegetables, $30 worth of poultry and 30 eggs.

Notices informing customers of the limits were placed in FairPrice stores, saying that supplies of daily essentials remain available.

"We urge customers to buy only what they need and not to stockpile," the notices said, adding that the purchase limits were set to ensure that as many customers as possible have access to popular items.

Malaysia's announcement on Monday night of a nationwide lockdown to prevent further spread of the coronavirus within the country saw Singaporeans flocking to supermarkets, concerned that food supplies from Malaysia will be impacted.

Long queues formed with trolleys and baskets filled with fruit, paper products and canned goods, and continued yesterday.

FairPrice said checkout queues were more orderly and customers were buying more responsibly than a similar episode early last month, when the national disease outbreak response level was raised to "orange".

It has increased its inventory holding for certain products. Delivery runs from its warehouses in Singapore have also been stepped up.

"FairPrice stands ready to ensure daily essentials remain available for Singapore," said chief executive Seah Kian Peng.

"We want to assure Singaporeans that we have sufficient stocks."