Associations representing agencies in Germany, Austria and Switzerland have urgently advised members not to sign "Preferred Fares" contracts with Lufthansa.
Under this preferred fares scheme, agents would have to pay a surcharge on certain fares if booked through the GDSs.
But they will also have to sign a contract with Lufthansa to gain access to these fares.
The DRV, VIR, ORV and SRV, the agents' associations in the three countries, plus the VDR, representing German travel managers, condemned the airline's programme as being against the consumers' interest.
In a joint statement, the associations said Lufthansa's plans were not compatible the needs of travel agents for efficient sales methods, market transparency and fair play.
The associations also said Lufthansa's use of the word "Preferred" was misleading as prices would actually go up.
They said they did not want to get involved in any battle between Lufthansa and the GDSs and demanded that all sales channels should be equal and offer the best possible processes for booking, fulfillment, invoicing at a reasonable cost.
Lufthansa and its fully-owned airline sister-airline SWISS announced their new programme last month.
Under the proposals, one way fares on Lufthansa and SWISS will go up by 15 one way and 30 for a round trip on tickets bought in Germany and Austria from July 1.
Prices for tickets bought in Switzerland and Liechtenstein will go up from October 1.
But the carriers said they would continue to make available the current lower fares after those dates.
These will be called "preferred fares" and will be subject to the surcharge if booked through a GDS.
Lufthansa will charge agencies 4.90 plus VAT per coupon and SWISS will charge CHF8 (5) per booking.
If the preferred fares are booked through the two carriers' travel agent portals, or direct from the airlines' websites, call centres or ticket counters, there will be no fee.
At the same time the carriers said it would no longer publish web-only fares.
The move has attracted criticism. Amadeus, the biggest GDS in Central Europe and also partly owned by Lufthansa, and ECTAA/GEBTA, the European agents'assocaition, have both condemned Lufthansa's actions.
A spokesman for Lufthansa said spent it spent 200m a year on “sales related costs which go to the GDSs” and it had prepared the market a year ago that it was going to do soemthing about it.
He said that while the airline was talking to the agents "we are saying why we are doing this but we are not discussing the scheme or looking for another solution."
He declined to comment on the agent associations' decision advising members not to sign, saying it was a matter for them.
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