Taiwan said Tuesday it will ask US tech giant Apple to blur satellite images of sensitive military installations which are freely available to iPhone 5 users.

The defence ministry reacted after the Liberty Times newspaper printed a satellite picture, downloaded with an iPhone 5, showing a top-secret long-range radar base in the northern county of Hsinchu.

"Regarding images taken by commercial satellites, legally we can do nothing about it," the ministry's spokesman David Lo told reporters.

"But we'll ask Apple to lower the resolution of satellite images of some confidential military establishments the way we've asked Google in the past," he said, referring to the Google Earth programme.

Apple has not yet received a formal request, according to Bravo, a Taiwan PR company handling its media relations. It declined to speculate how Apple would respond to a request.

The Hsinchu base houses a cutting-edge long-range radar procured from the United States in 2003. Construction of the radar is expected to be completed by the end of the year.

The ultra-high-frequency radar, supplied by US defence group Raytheon, is capable of detecting missiles launched as far away as Xinjiang in China's northwest, military officials say.

They say the radar, which cost Tw$36 billion ($1.23 billion), is designed to give Taiwan minutes of extra warning in case of a Chinese missile attack.

Taiwanese experts estimate China currently has over 1,600 ballistic missiles aimed at the island.

The number appears to have continued to rise despite improved relations since 2008 when Ma Ying-jeou of the China-friendly Kuomintang party became Taiwan's president.

Beijing still sees the island as part of its territory awaiting reunification, by force if necessary, even though Taiwan has governed itself since 1949 at the end of a civil war.