NEW YORK — Boeing Co. postponed the delivery of its first 787 to the middle of the first quarter of 2011, compounding a string of delays for the jetliner that is already more than two years past its original scheduled debut.

The latest delay is the result of engine delivery problems, Boeing said in a statement early Friday. The Chicago company said in July it expected to deliver the plane late this year, but it warned that might not happen. It had said at that time that a series of problems, including supplier work related to parts of the tail and instrument issues that might push the first delivery “a few weeks into 2011.”

The 787’s first customer, Japan’s All Nippon Airways, said in a statement the delay is regrettable especially “given the success of the flight test program so far.”

“However, we trust that the time will be used to deliver the best possible aircraft in the shortest possible time frame.”

The 787, which Boeing calls the Dreamliner, is made of many composite materials designed to make it lighter and more fuel-efficient than comparable planes already in the sky.

Despite delays, the 787 remains Boeing’s best-selling new plane, with more than 850 orders.

It lists for $150 million to $205.5 million, depending on the model, but major customers routinely get discounts.

Boeing said the delay won’t affect its financial expectations.

Boeing spokeswoman Yvonne Leach said the company is working closely with British engine manufacturer Rolls-Royce to expedite engine deliveries, but current flight tests are continuing as planned.

Rolls-Royce said the delay was not related to the reported failure of an engine in a recent test.

“We have been informed by Boeing that the currently planned dates for Trent 1000 engine deliveries will not support their latest flight test program requirements,” Rolls-Royce said in a statement Friday.

However, Rolls-Royce confirmed “that the engine availability issue is unrelated to the test bed event which occurred earlier this month.”

The FlightGlobal website, an aviation news site, reported this week that a Trent 1000 engine suffered an “uncontained” failure — meaning debris broke out of the engine casing — during a test on Aug. 2.