BEIJING, May 7 (Reuters) - China's COMAC is expanding production facilities for its homegrown C919 jets in Shanghai, according to one of the project contractors, as the state-owned planemaker ramps up manufacturing to fulfill hundreds of new orders.

China Aviation Planning and Design Institute (Group) Co. Ltd. (AVIC-CAPDI), a state-owned provider of aviation planning and construction services, said on its WeChat account at the end of April that the company had "recently won the bid for the second phase of the C919 large passenger aircraft batch production capacity construction project".

AVIC-APC said the project was in Pudong, Shanghai, and had a total construction area of 330,000 square meters. COMAC is headquartered in Shanghai.

"The completion of the project will meet the future batch production needs of the C919 large passenger aircraft, effectively improving its production efficiency and providing strong support for the commercial operation and market competition of domestically produced big aircraft," it said.

The second phase of the project, according to AVIC-CAPDI, mainly includes the construction of assembly plant, parts warehouse, and tarmac area.

It was not immediately clear what the first phase of the project is.

AVIC-CAPDI's statement was widely reported by local media on Monday but was deleted by the company on Tuesday. AVIC-CAPDI and COMAC did not immediately respond to requests for comment.

The factory expansion comes as Air China and China Southern Airlines, two of the country's largest carriers, placed orders amounting to 100 C919 jets each, expanding commercial operations of the plane amid ambitions by Beijing to take market share from industry leaders Airbus and Boeing.

The C919 has so far gained more than 1,000 orders, but mostly from Chinese airlines and aircraft lessors including China Eastern Airlines, the maiden user of the jet, which currently operates five C919 on three domestic routes.

Last year, government-backed media The Paper said China expected to reach annual production capacity of 150 C919s in five years.

China has said it wants to secure broader international recognition for the C919 this year, including pursuing European Union Aviation Safety Agency certification, and has been marketing the jet in South East Asia. (Reporting by Sophie Yu and Brenda Goh; Editing by Mark Potter)