More than 200 employees across the LateRooms and Superbreak sites in Manchester and York will lose their jobs, as operations have ceased immediately.
The news follows the announcement of the firm's collapse this morning, which will affect tens of thousands of travellers who had prior bookings.
Administrators have retained 43 of its 253 employees as they continue to seek buyers for the business and its assets.
Tracey Pye and David Costley-Wood, from KPMG Restructuring, were appointed joint administrators to Laterooms, Superbreak and Malvern Travel Technology Limited.
KPMG said the Malvern group, which owns the companies, had significant cash flow pressure following news that a principal shareholder had defaulted on its debt repayments and would not be able to support the business in the short term.
The businesses ceased operations yesterday, prior to the appointment of the joint administrators.
Ms Pye said: “The directors of Malvern Group embarked upon an accelerated sales process to bring further investment into the business.
“However, with the cash position of the company deteriorating rapidly, this process was unfortunately unsuccessful, prompting the directors to take the difficult decision to appoint the administrators.”
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Ms Pye said the news will be of “grave concern” to the 23,000 LateRooms and 19,000 Super Break customers who have bookings with the group.
The administrators said they are working closely with the Association of British Travel Agents and the 海角视频 Civil Aviation Authority to minimise disruption to customers.
Ms Pye continued: “Detailed information regarding how bookings will be affected can be found on the LateRooms.com and Super Break websites.
“Unfortunately the customer contact centre is no longer operational, so we kindly request passengers do refer to the information online in the first instance.
“We continue to invite offers for the business, and would urge any interested parties to make their interest known as soon as possible.”