BERLIN, Aug 19 (Reuters) - Two German warships await orders from Berlin, their commander said, to determine whether next month they will be the first German naval vessels in decades to pass through the Taiwan Strait, drawing a rebuke from Beijing.

While the U.S. and other nations, including Canada, have sent warships through the narrow strait in recent weeks, it would be the German navy's first passage through the strait since 2002.

China claims sovereignty over democratically governed Taiwan, and says it has jurisdiction over the nearly 180-km (110 miles) wide waterway that divides the two sides and is part of the South China Sea. Taiwan strongly objects to China’s sovereignty claims and says only the island’s people can decide their future.

The Taiwan Strait is a major trade route through which about half of global container ships pass, and both the United States and Taiwan say it's an international waterway.

"The decision has not been taken yet," the commander of the naval task group, Rear Admiral Axel Schulz, told Reuters in a telephone interview, adding the weather would play a role.

"We are showing our flag here to demonstrate that we stand by our partners and friends, our commitment to the rules-based order, the peaceful solution of territorial conflicts and free and secure shipping lanes."

Asked about the German ships' potential passage, China's foreign ministry said Taiwan was an internal Chinese affair and the key to stability was opposing Taiwan's independence.

"China has always been opposed to the undermining of China's territorial sovereignty and security under the guise of freedom of navigation," ministry spokesperson Mao Ning told reporters in Beijing.

Before their possible passage through the strait next month, the frigate Baden-Wuerttemberg and the replenishment ship Frankfurt am Main plan to call in Tokyo on Tuesday. They will also make stops in South Korea and the Philippines.

They will take part in exercises in the region with France, Indonesia, Italy, Japan, Malaysia, Singapore, the Philippines, and the United States.

Over the last four years, Beijing's military has increased its activities in the strait.