More than 1,800 workers are set to lose their jobs at Oasis and Warehouse and two other brands, after administrators said they were unable to find a buyer for the business.
Deloitte said that all stores will close indefinitely and online sales will be stopped.
Oasis and Warehouse run over 100 stores across the UK and Ireland.
Earlier this month, the High Court appointed provisional liquidators to the Irish arms of Oasis and Warehouse.
The order was sought in relation to Oasis Fashions Ireland Ltd, and Warehouse Fashion Ireland Ltd, which the court heard is part of the Aurora Fashions group - owned by the Icelandic Kaupthing Bank.
The order to wind up the two firms, which between them employ 248 people at 13 stores and 29 concession stands in Ireland, comes after administrators were appointed to its UK parent.
Deloitte said today it had sold the intellectual property and the company's stock to restructuring expert Hilco Capital, but Hilco had decided not to buy the rest of the business.
"Covid-19 has presented extraordinary challenges which have devastated the retail industry.
"It is with great sadness that we have to announce a sale of the business has not been possible and that we are announcing so many redundancies today", Administrator Rob Harding said.
"This is a very difficult time for the group's employees and other key stakeholders and we will do everything we can to support them through this," he said.
"We would like to thank all the employees and other key stakeholders in the group for their continued support," he added.