Chinese Vice Foreign Minister Zhang Zhijun summoned Vietnamese ambassador to China Nguyen Van Tho Thursday to lodge the complaint, the China Daily reported.
The Vietnam National Assembly passed the "Vietnamese Law of the Sea" Thursday, which describes Xisha Islands and Nansha Islands in the South China Sea as being within Vietnam's sovereignty and jurisdiction.
Reaffirming that China has "indisputable sovereignty" over the islands and their adjacent waters, Zhang said the law infringes upon China's sovereignty.
"China strongly protests and firmly opposes such a move by Vietnam. Vietnam's action is illegal, invalid and detrimental to peace and stability in the South China Sea," he said.
The minister said Vietnam's unilateral action has complicated and escalated the problem in the South China Sea, he said.
China requested Vietnam to immediately rectify the mistake and refrain from taking any action that could damage bilateral relations or jeopardize the peace and stability of the South China Sea, said Zhang.
The Chinese foreign ministry also issued a declaration protesting the law.
The declaration said it was unlawful and invalid for any other country to claim sovereignty over the concerned islands.
Beijing: China on Thursday lodged a protest with Vietnam concerning the recent passing of a Vietnamese maritime law that extends the country's jurisdiction to islands claimed by China.
First Published: Thursday, June 21, 2012, 18:36