Shelves at a Tesco Lotus store are left empty as consumers stock up on basic consumer goods and rice amid fears over the spread of the coronavirus. Pitsinee Jitpleecheep

Shoppers in Greater Bangkok are quickly emptying supermarket shelves of long-lasting items like instant noodles, packed rice, tissue paper, tinned fish and drinking water as fears mount over the coronavirus epidemic.

Large retail operators including Tops Supermarket, Tesco Lotus, The Mall Group and Big C Supercenter acknowledged that these items have been snapped up quickly since the weekend.

They are also in consensus that fear of the deadly virus is the primary cause for the shopping spree.

"We have never seen these kinds of purchases," said Chairat Petchdakul, vice-president for supermarket merchandising at The Mall Group Co, the operator of Gourmet Market.

"At first we thought it stemmed from the payday, but the majority of the goods the shoppers bought were long-lasting items like instant noodles, drinking water and tinned fish," he said. "We then assumed that the demand was from growing concerns about the coronavirus epidemic. However, we will closely watch shoppers' behaviour again during these weekdays."

Mr Chairat gave assurances that supplies of the mentioned products are adequate, though with perhaps a slight delay in delivery from producers.

The Mall Group says it has doubled the inventory of goods from a 15-day supply to 30 days to prevent shortages and ensure that consumers have a sufficient supply of the products they are looking for.

A worker at the Gourmet Market in Siam Paragon, who asked not to be named, said shoppers were forming long queues at the tills to pay for groceries last weekend.

Workers at the Tops Chidlom branch, Big C Supercenter at Future Park Rangsit and Tesco Lotus on Nakhon In Road in Nonthaburi made similar observations of the buying phenomenon since last Friday.

Mintita Thowkam, 33, a company employee, said she's begun hoarding goods because she is afraid of the coronavirus and is not confident in the government's measures to control the spread.

"I don't know whether the government's agencies have efficient measures to handle big groups of Thai workers who are coming from South Korea," she said. "If the measures are not serious enough, the outcome will be terrible."

Thailand's embassy in Seoul has been informed by the South Korean Immigration Office that more than 5,000 Thais reported to the office from December last year to March 1, according to the Foreign Ministry.

"I'm quite worried about this, so I came to Tesco Lotus hypermarket for products to stock up for 1-2 months," Ms Mintita said, adding that she also found some products missing from shelves on Tuesday, including Mama instant noodles with tom yum kung flavour.

Pun Paniengvait, manager of the president's office at Thai President Foods Plc, the maker of Mama instant noodles, said supplies are assured because total production capacity for all instant noodle brands, excluding imported products, is about 10 million packets a day.

Production utilisation is now 70-80%, so production could still be extended to 15 million packets per day.

Per capita consumption of instant noodles in Thailand is about 45.9 packets per year.

"Don't worry about a product shortage," Mr Pun said. "The capacity is more than enough to serve the whole Thai population."