(Beijing) – Four top Chinese airlines have said they will no longer sell their tickets on a top travel booking site because of a rise in consumer complaints over high prices and fees.

China Eastern Airlines and Air China said on Weibo, the Chinese version of Twitter, on January 4 that they will stop selling plane tickets on Qunar.com because of an increase in complaints about overpriced tickets and extra charges for changes.

China Southern Airlines, Hainan Airlines and two of their subsidiaries released similar statements on December 31.

The four airlines are the biggest in the country in terms of passengers per year.

Qunar, which was founded in 2005, is owned by the Internet search company Baidu Inc. It provides a platform for airlines and travel agents to sell tickets, and also allows travelers to make hotel bookings. The company's website says it had 9,000 registered travel agents as of March 2015.

An employee of one of the airlines who asked to remain anonymous blamed the spat on unscrupulous ticket sellers, but also said that Qunar has been slow to address the problems.

"For example, legitimate airlines and agents will tell customers if a ticket is refundable or changeable," the person said. "But some agents are redeeming miles to get ticket. These kind of tickets are not refundable, but the agents won't mention that to customers on Qunar's website."

When customers have problems, such as flight delays, cancellations and schedule changes, they complain to airlines instead of the agents they bought the tickets from, the airline employee said. By cutting ties with Qunar, the airlines will no longer be accountable for these complaints, the source said.

Qunar said in a statement on December 31 that the dispute is not about customer complaints but rather about how tickets are ranked on the website. China Southern Airlines and Hainan Airlines asked Qunar to arrange tickets according to when they are released rather than by price, but the website wanted to display them by price because that was what customers wanted, the statement said.

Qunar did not publish a statement after China Eastern Airlines and Air China said they were severing ties.

Qunar's statement pointed out that travelers can still buy tickets for the four airlines through travel agents on its website.

(Rewritten by Chen Na)