Takings at the till plunged by 40.5 per cent year on year, according to data out by the Department of Statistics on Friday (June 5). Excluding motor vehicles, retail sales fell 32.8 per cent.
The sale of food and beverage (F&B) services showed a similar trend, decreasing 53 per cent.
Circuit breaker measures, which started on April 7 and ended June 1, caused all non-essential businesses to close, including retail stores.
F&B establishments could not allow dine in customers, but only provide takeaway or delivery services.
Sellers of discretionary items were hit the hardest by these moves, with the sales of watches and jewellery dropping 87.8 per cent. Retailers of wearing apparel and footwear also saw takings drop 85.3 per cent.
Sales at department stores also plunged some 84.6 per cent, due to the closure of physical stores for most of the month, the Department said.
Motor vehicle sales fell 77 per cent, while the sale of optical goods and books slid 64.5 per cent.
Recreational goods takings dropped 63.4 per cent, while food and alcohol sales decreased 53.4 per cent.
Sales at petrol service stations, cosmetics, toiletries and medical goods and furniture and household equipment also registered double-digit declines.
But sales at supermarkets and hypermarkets rose 74.6 per cent, as essential stores remained open.
Minimarts and convenience stores also saw an increase in takings of 10.7 per cent.
For food and beverage services, restaurants bore the blunt of the blow, with sales dropping 66.9 per cent.
Food caterers saw a decrease of 59.8 per cent, while cafes, food courts and other eating places saw a drop of 45.5 per cent.
Meanwhile, fast food outlets also saw declines of 28.6 per cent.
The total sales value of food and beverage services stood at $397 million, with online sales making up a large 39.2 per cent.
Total retail takings in April was $2.1 billion, with online sales making up 17.8 per cent, more than double the share in March.