Japan's top government spokesman on Tuesday expressed concern over China's call to require foreign airlines to label Taiwan as part of China.

"Generally speaking, it's not favorable that the government requires (private companies) to take steps in line with a certain political position," Chief Cabinet Secretary Yoshihide Suga said at a regular press briefing.

His remarks came after Japan Airlines Co. and All Nippon Airways Co. changed their descriptions of Taiwan on their websites for Chinese customers to "Taiwan, China" in response to China's request made in April.

China regards Taiwan as a renegade province and has threatened to invade should the island's government formally declare independence.

Taiwan's Foreign Ministry on Monday protested at the changes made by the two major Japanese airlines.

The Associated Press reported last month that it found 20 carriers, including Air Canada, British Airways and Lufthansa, that now refer to Taiwan as a part of China on their global websites.