Taiwan's military revealed Monday it is investigating the disappearance of a laptop containing sensitive information, including naval communications codes.

The laptop, which belonged to a private contractor, went missing two weeks ago from a docked Kuang Hua VI-class stealth missile ship. It was connected the the vessel's main computer and used to test confidential communication equipment and procedures.

Opposition lawmakers fear Chinese spies stole the laptop in order to gain access to modern military technology, according to Fox News.

Lin Yu-fang, a lawmaker with the Legislative Defense Committee, told the Boston Globe that while the laptop did not contain any "crucial" secrets, it indicated a security loophole that could undermine the island's defenses against a possible Chinese attack.

"If China obtained the laptop, it would get the navy's highly sensitive communications code as well as related missile data," said Erich Shih, an editor at Taipei-based Defence International magazine, told the AFP.

The ship was one of 10 deployed by Taiwan in 2010. According to RT, each vessel is equipped with four Hsiungfeng II anti-ship missiles with a range of about 93 miles.

Mainland China has a history of conducting espionage against Taiwan and the United States.

In March, Taiwan detained one of its own air force captains who was accused of spying for the Chinese, according to Military News. Air force Capt. Chiang was the fourth member of the Taiwanese military to be charged with spying for China in 14 months.

In April, the U.S. Defense and State Departments released a joint report outlining Chinese espionage against the United States. According to the report, China is stealing civilian and military space technology in order to "disrupt U.S. access to intelligence, navigation and communications satellites."

Although Taiwan and China have been governed separately since the end of a civil war in 1949, Beijing still considers the island part of its territory.

Tensions between Taiwan and the mainland have eased since 2008, following President Ma Ying-jeou's rise to power. Current Taiwanese policies toward China emphasize trade and tourism, but the mainland has still not ruled out the use of force against the island, according to the AFP.