MONTREAL -- Bombardier has delayed the first flight of its new CSeries jet by a month, the second delay of its new flagship passenger aircraft.

The Montreal-based company said the inaugural flight of the CS100 plane, which had been slated to take place in June, is now scheduled by the end of July.

It's the second delay for the much-anticipated aircraft, which is expected to compete with some of the smaller planes made by Boeing and Airbus.

In December, Bombardier (TSX:BBD.B) pushed out the timing of the first flight by six months after falling behind its original plans late last year.

The latest delay will give Bombardier more time for additional software upgrades and final tests such as low and high-speed taxiing and engine power-on.

"We're very, very confident that we're going to be able to go through these items and fly by the end of July," Bombardier spokesman Marc Duchesne said in an interview Wednesday.

"It's a very complicated program, it's a very modern aircraft...and over the length of this program this is very minor because the program will last at least 20 years."

Duchesne said no other parts of the program, including first deliveries set to begin in a year, are affected by the flight delay.

He said Bombardier officials approved the delay on Tuesday after returning from the Paris Air Show, one of the major events in the global aviation industry.

The aircraft manufacturer has applied for to Transport Canada for a flight test permit after having completed ground vibration tests, software upgrades and corresponding tests on its first test flight aircraft.

Walter Spracklin of RBC Capital Markets said markets were expecting the first flight to occur within days.

"While a push of first flight by a month is not material from a cost/development perspective, it will likely impact negatively near-term sentiment and again call into question the readiness of the CSeries avionics and fly-by-wire system," he wrote in a report.

Bombardier has received 388 commitments for two versions of the 110- to 160-seat aircraft, including 177 firm orders.

On the Toronto Stock Exchange, Bombardier's shares lost 13 cents, or 2.78 per cent, at $4.54 in Wednesday morning trading.