Japan's ANA Group will begin introducing women-only lavatories on ANA Group international routes from March 1.

The carrier says the move follows "numerous requests" from passengers.

One women-only lavatory will be designated in the aft section of the passenger cabin (the location may differ depending on aircraft and configuration) and will be available for use by women passengers in all classes of service. The change will not be implemented on routes serviced by smaller Airbus A320 or Boeing 737 aircraft.

ANA says there will be some occasions when men can use the restrooms:

* When required for safety reasons, just prior to the seat belt sign being turned on during take-off and landing.
* When a passenger is not feeling well and a personal emergency requires such use.
* When there are very few female passengers and the women-only designation has been lifted for the flight.

ANA (All Nippon Airways) is the seventh largest airline in the world by passenger load (IATA ranking) and Japan's largest domestic carrier. It carries almost 50 million passengers every year to 50 destinations in Japan and 23 cities throughout Asia, Europe and the US.