Paul Stanley and Dean Watson of Begbies Traynor have been appointed joint liquidators after the company was recently served a winding up order.
Omega’s accounts recorded turnover just shy of £300 million last year.
The company’s Atol was suspended on September 3 after it defaulted on its Iata billing and settlement plan (BSP).
The CAA has confirmed the company opted not to renew its Atol ahead of the September renewal deadline.
It had been licensed to sell 4,069 Atol protected holidays this year.
Milton Keynes based Omega traded under Omega Travel, Omega Flight Store, Sagitta Travel Agency, Newtrip, Jade Travel, Far East Travel Centre and Chinese Travel Shop.
The business, which was founded in 1965 and specialised in travel to and from the Far East, had recently changed its name to Milburn Travel.
It had locations in London, Manchester, Edinburgh and Birmingham and largely sold flight-only bookings.
Stanley and Watson of Begbies Traynor were this week announced as joint compulsory liquidators.
They have launched an “urgent investigation” to recover “substantial amounts” owed to the company’s creditors, including airlines.
Stanley, regional managing partner at Begbies Traynor, said: "The official receiver appointed us as liquidators within 24 hours of the winding up order being issued. This demonstrates the urgency of action being taken and the magnitude of the numbers involved.
“We are already arranging interviews with staff and directors at the company as well as liaising with creditors. We are at an early stage in proceedings but we are making significant progress and have identified at least £20m owed to creditors.
“We will update interested parties as we advance our detailed investigations into the exact whereabouts of the company’s assets.”