The indoor market will now be open from Wednesday to Saturday, with opening hours of 8.30am to 4.30pm.
A Barnsley Council spokesman said the move was to 'allow stallholders to replenish stock, while also reducing pressure on staffing levels, especially with school closures and self-isolation measures'.
Traders have been given the option of trading outside the market on both or either of the affected days.
The spokesman said: "The council is working with and supporting traders through this unprecedented time.
"Locals are encouraged to support local businesses and continue shopping locally.
"The situation is constantly evolving and the council will continue to track and follow government advice and guidance."
A home delivery service is available on the ShopAppy website or mobile app.
Like a supermarket home delivery service, shoppers can have their items delivered to their doorstep between 9am and 4pm on any chosen day.
The town's taxi drivers have been enlisted to deliver goods.
People can also click-and-collect from the market's collection point, on the May Day Green entrance, between 1pm and 7pm on market days.
Visit www.shopappy.com/barnsley for more information or to book deliveries.
Anyone with additional requirements for delivery should call 772239.