Redundancies for staff working for Wilko will start next week after a bid for the retailer fell through.
Earlier this week there was a last-minute bid to save the high street retailer and its stores across the country, including ones in Suffolk.
The GMB union has said most staff working in the commercial trading team and IT, finance, legal and HR divisions for Wilko will have their "last day with the company" on Monday.
Redundancies are due to start next week for warehouse staff.
Earlier this month Wilko announced it was on the brink of collapse after filing for administration and putting 12,500 jobs at risk.
When the administration was announced, chief executive officer Mark Jackson said: "We don't today have an offer that provides the necessary liquidity in the time we have available, given the mounting cash pressures we're faced with".
Read More: Suffolk Wilko stores at risk of closure as firm on brink of collapse
The retailer has stores in Ipswich, Bury St Edmunds, Midenhall and Lowestoft.
The Ipswich store launched a huge administration sale only a few weeks after the announcement was made.
The last-minute bid to save the retailer was put forward by restructuring specialist M2 Capita.
The Guardian reported £90m to keep the entire Wilko chain trading.
Andy Prendergast, GMB union secretary, said: "The devil is in the detail but any bid that guarantees jobs must be prioritised.
"However now the bid has fallen through which puts staff and stores at risk.
"GMB said it remains hopeful that there is a "viable buyer on the table" which could protect staff in stores and online, but that it must "continue to prepare for the worst".
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