Japan's bar association is urging a Malaysian low-cost carrier to apologize to a Japanese man with disabilities after it refused to check-in his electric wheelchair, eventually causing him to miss his flight at Kansai airport.

The Japan Federation of Bar Associations said on Wednesday it also demanded that the airline, AirAsia X, correct such treatment of people with disabilities, calling it an "abuse of human rights," and ensure it does not happen again.

The airline has not responded to the letter.

According to the association, AirAsia X in March 2014 refused to check-in the man's wheelchair at Kansai International Airport as luggage on the basis of weight, although it was below the 85-kg limit designated by the airline.

The wheelchair was about 80 kg and he had also informed the airline of its size and weight beforehand. The man was to fly to Kuala Lumpur.

"The weight of the wheelchair was not as much as to have troubled the plane in flying, and the denial of his boarding is a discriminatory action that violated the freedom to move," the association said in the letter dated last Thursday.