China Southern Airlines has signed an agreement with Airbus to buy 10 Airbus A330-200s but the deal is subject to shareholder and Chinese government approval.

The airline says in a statement it has signed an agreement with Airbus to purchase 10 A330-200s for delivery from March 2010 to August 2012.

It says each aircraft, including engines, is worth around $170 million and China Southern will pay for the aircraft in cash and bank financing.

The statement fails to mention the engine type but according to Flight’s ACAS database Rolls-Royce powers the six A330-200s already in the airline’s fleet and until now the airline has had no A330-200s on order.

Even though China Southern has signed an agreement, the airline says the purchase is subject to approval from shareholders and China’s government.

The 10 A330-200s are needed to “improve the company’s operating capacity in order to accommodate the continuous growth in demand for aviation services” in China, it adds.