All of Wilko’s 400 stores are set to close by early October, the GMB union has said.
It means redundancies now look likely for all 12,500 staff at the high-street chain.
The retailer had already confirmed that 52 stores would shut this week, leading to 1,016 redundancies, with hundreds of other job losses across the business.
Wilko has four stores in North Yorkshire, on Stirling Road at Clifton Moor in York; in the Abbey Walk Shopping Centre in Selby; on Northallerton High Street; and in the Balmoral Centre, Scarborough.
None of them were among the first 52 due to shut.
The GMB union, which represents more than 3,000 Wilko staff, revealed that a further 124 stores are due to close next week, with these set to shut between 19 September and 21 September.
It comes after a last-ditch attempt by the owner of HMV to strike a rescue deal for the retailer collapsed.
Administrators for the high street chain had been in discussions with Doug Putman, who bought the entertainment chain in 2019, over a deal to buy around 200 Wilko shops.
GMB said the failure to secure a deal meant that remaining offers on the table are only likely to purchase a number of Wilko store properties, and are not expected to include workers.
PwC, who are overseeing the administration, has already agreed a roughly £13 million deal to sell up to 51 Wilko stores to rival B&M.
Fellow discount retailer Poundland is still in talks with PwC in an attempt to snap up around 100 shops, according to Sky News.
Other high street chains including The Range and Home Bargains have also reportedly signalled their interest over potentially buying the Wilko brand or stores.
Nadine Houghton, GMB national officer, said: “This isn’t a tragedy without cause. Wilko should have thrived in a bargain retail sector that is otherwise strong, but it was run into the ground by the business owners.
“Money was siphoned out of the business for dividends, warnings about what needed to be done to save the business were not heeded and advice around what the business had to do to thrive was not listened to.
“No worker caused the downfall of Wilko. But they will be the ones who will suffer – all as the owners get off scot-free.
“GMB will not stop campaigning for the owners of this debacle to be held to account.”