Mitsubishi Aircraft Corp. has pushed back the maiden flight and delivery schedule of its Mitsubishi Regional Jet by at least a year, citing delays in the development schedule.

The MRJ will now make its inaugural flight in the final quarter of calender 2013, while deliveries will commence in summer 2015 at the earliest, the company said on its website Wednesday.

The jet's first flight had previously been scheduled for later this year and the first delivery in 2014. The postponement will likely hinder the plane maker's efforts to challenge the supremacy of Bombardier Inc. and Embraer SA in the regional jet market, which is expected to expand significantly in the near future.

The sector, which covers planes seating 70 to 100 passengers, could see global sales top 5,000 units over the next 20 years, the company said Wednesday.

The unit of Mitsubishi Heavy Industries Co. said postponing the first flight will allow it to confirm fabrication processes and complete technical studies on the jet, but did not elaborate further.

The company has already secured 70 firm orders for the MRJ from All Nippon Airways Co., Trans States Airlines Inc. and ANI Group Holdings Ltd. The three companies have also taken combined options for another 60 of the jets.

"If we suffer losses, then naturally we would ask for compensation" from Mitsubishi Aircraft, said Yoichi Uchida, a spokesman for ANA, the first carrier to place an order for the MRJ.

"We haven't calculated the impact (of the delay) on our operations yet," Uchida added.

In February, Mitsubishi Aircraft said it would announce a new schedule for the MRJ because of what it described as development "challenges."