Ryanair would be interested in bidding for the whole of insolvent German carrier Air Berlin, but it needs access to more data on the airline's finances, Chief Executive Michael O'Leary told Reuters.

"We would be very happy to bid for the whole of Air Berlin, which is generally a short-haul, domestic, intra-EU carrier," O'Leary said by telephone.

"But we don't know how much restructuring it will take, how much money is it losing, why is it losing so much money in a market where we make money," he said.

O'Leary complained that the Air Berlin insolvency process is a "stitch-up" to help strengthen Lufthansa. "What's going to be left by the time Lufthansa completes the discussions?" he asked, referring to comments last week that Lufthansa was first in line for talks.

Air Berlin CEO Thomas Winkelmann however was quoted in an interview with Handelsblatt daily as saying the "data room" giving details on its finances had been open since May, when it first said it was looking for partners.

"Mr. O'Leary is wholeheartedly invited to help us save jobs," a spokesman for Air Berlin said.

Ryanair said Winkelmann's comments on the data room seemed out of date considering the insolvency filing was only made this month.

O'Leary told Reuters Ryanair needed information on Air Berlin's leases, employment contracts and terms with airports before it could determine how much restructuring it would need.

Ryanair uses Boeing 737 planes, while Air Berlin flies Airbus A320s, but O'Leary said Ryanair would use those Airbus aircraft to continue Air Berlin's operations in the event of a takeover.

O'Leary said Ryanair, which bought budget carrier Buzz from KLM in 2003, was keen to play a role in the changes going on in the European airline industry.

It has also said it would be interested in taking on insolvent Alitalia if it can be restructured.

"We are clearly going to play a role in the consolidation of the European airline industry, given that we're the biggest airline in Europe," O'Leary said.

He predicted that in five years' time there would be only four or five airline groups in Europe - Ryanair, Lufthansa, Air France-KLM, British Airways parent IAG and possibly easyJet.

"Everything will all get consolidated into four or five big groups. It's always hard to predict the demise of an individual airline but that's what happens," he said.