The Commercial Aircraft Corporation of China (Comac) on Monday received 20 more orders for the C919 aircraft, which brought the total orders to 400.

The Comac and Industrial Bank Financial Leasing signed a contract for the new orders on Monday.

The orders for C919, China's largest domestically produced aircraft, have showed the increasing demand and confidence in aircraft made in China, said Tian Min, chief accountant of the Comac.

The Comac C919, which will compete with the Airbus A320 and Boeing 737 family of aircraft, was scheduled for its first flight next year, but that has now been delayed until 2015.

Tian said a modern commercial aircraft is comprised of millions of parts and dozens of complicated systems and also a project involving hundreds of work units home and abroad. "This adds difficulty and complexity to project management."

Meanwhile, use of new materials and technologies increased difficulty and risks in the development of the aircraft, Tian said.

"For safety concerns, it is quite necessary to postpone the maiden flight of the C919," said Tian.