In Mr Faisal Mohamathu's minimart in Tanjong Pagar, tinned food and instant noodles fill the shelves while bags of rice and toilet paper are neatly stacked at the back.

These are items that have been flying off the shelves at supermarkets across Singapore over the past month, as increasingly tighter measures have been put in place to stem the community transmission of the coronavirus.

But Mr Mohamathu laments that he does not get the same crowd as the FairPrice outlet in nearby Tanjong Pagar Plaza.

"It's very tough to do business nowadays," said the 35-year-old, who has run Alfa H Mart, located on the ground level of The Pinnacle @ Duxton, for almost six years.

Without office workers and students to patronise his store since the start of the circuit breaker period, his sales are now dependent on nearby residents and have dropped by 30 per cent.

A check on nine grocery stores across several Housing Board estates paints a similar picture - the long queues at supermarkets seldom spill over to the smaller players.

Their smaller range of goods and less competitive prices have been pinpointed as the main reasons for their slower business.

They also lose business when they run out of sought-after staples, such as instant noodles and flour, because suppliers do not prioritise their orders.

Membership points and rebates at the big supermarket chains also lure customers away from family-run minimarts and provision shops.

Ms Mabel Foong, 49, who manages Kai Soon Supermarket in Hougang, said: "At FairPrice, you can get points, Sheng Siong has lucky draws. How can our minimart compete?"

Sales pick up only when some customers look to them to skip the long queues at the nearest FairPrice outlet, she said.

Mr Lian Jia Low, 26, manager of 48 Vegetable which has three stores selling fresh produce and a selection of non-perishable items, said its turnover has fallen by 40 per cent as most flock to nearby wet markets or supermarkets.

The crowd around his store in Bedok North Street 1 has thinned drastically. "There are fewer people out now, so competition among shops is fiercer," he said.

But it is a different story for mid-sized supermarkets and minimart chain stores.

These grocery chains, which offer a wide variety of goods comparable to the big names, have seen a boost in sales, especially on panic-buying days after major announcements from the Government.

Mr William Heng, 54, executive director of Heng's Family Group, which has 11 minimarts, said: "Every time Prime Minister Lee Hsien Loong makes an announcement, my business will be good because people will start queueing up outside.

"On the one hand, I wish there'll be announcements every day, but on the other, when people hoard, my staff have to work harder."

Overall footfall has fallen by 10 per cent on regular days, but sales have not been badly hit, he added.

Sales at grocery chain U Stars Supermarket have surged by almost 50 per cent across its 25 stores, including two 929 sq m hypermarkets in Keat Hong and Punggol.

Its head of corporate services Cliff Heng, 38, said: "Given that people can't travel far, they will go to whichever supermarket is closest to them, especially if they're buying groceries that are heavy."

Associate Professor Lawrence Loh from the National University of Singapore Business School said big players are often at the top of mind for many consumers as a one-stop shop. He added: "It's the young people who are going out to do the shopping these days, so naturally they like big brands and names. Some may go to supermarkets out of habit."

Ms Lim Xiu Ru, a lecturer at Singapore Polytechnic's School of Business, said smaller players are disadvantaged by their lack of a sophisticated supply chain system that can keep shelves stocked.