PARIS (Reuters) - Airbus (>> Airbus Group) is renegotiating delivery schedules for its revamped A320neo jet and has told some airlines it will be delayed by about two months, industry sources said.

The European planemaker missed a 2015 target for delivering the first aircraft, an upgraded fuel-saving version of its best-selling medium-haul jet, by a few weeks due to what it described as issues with documentation for new Pratt & Whitney engines.

Industry sources have pointed to delays in deliveries of the newly-developed Geared Turbofan engine from its U.S. manufacturer, a subsidiary of United Technologies (>> United Technologies Corporation).

There was no immediate word on the number of aircraft affected or the full range of expected delays.

Airbus and Pratt & Whitney confirmed they were in talks over deliveries, without elaborating.

"We are in talks with our customers on deliveries and once these talks will have concluded, then we'll finalize the aircraft and deliver to our customers as agreed," an Airbus spokeswoman said.

"We are in talks with our operator customers on delivery schedules and once these are concluded we will finalize the schedules as agreed," said a spokeswoman for Pratt & Whitney.

Although the delays are minimal compared with some all-new programs, the A320 and Boeing's competing 737 drive a large chunk of aerospace industry profits and are closely watched.

Airbus has said deliveries of the A320neo will be tilted toward the second half of the year.

The A320neo is designed to save 15 percent in fuel consumption. So far, Airbus has delivered one aircraft to Germany's Lufthansa (>> Deutsche Lufthansa AG).

The launch customer was originally supposed to be Qatar Airways but it rejected early aircraft due to longer than expected startup times, requiring extra fuel.

Speculation about last-minute fine-tuning resurfaced after the first aircraft was delivered after an unusually extensive series of 11 pre-delivery test flights, according to data from website Hamburg Finkenwerder News.

In December, India's IndiGo (>> Interglobe Aviation Ltd) said it would not receive its first A320neo on time for "industrial reasons" and warned of further delays.

United Technologies said last month the engines needed "a software fix and a minor hardware fix" to deal with cooling problems, but were meeting performance targets.

The A320neo is sold with engines from either Pratt & Whitney or CFM International, owned by France's Safran (>> SAFRAN) and General Electric (>> General Electric Company). CFM also powers the competing Boeing 737 family, including the revamped 737 MAX.

The first CFM-powered A320neo is expected to be delivered in July.

Boeing (>> Boeing Co) said on Wednesday it was working to deliver the 737 MAX ahead of schedule. The Wall Street Journal reported it could be delivered up to six months before the third-quarter 2017 target.

(Editing by James Regan and David Clarke)

By Tim Hepher