Washington, Jan 18 (Agencies): Boeing on Tuesday resumed flight tests of its 787 Dreamliner in the hope of winning over US regulators after a string of technical mishaps and delays.

"Boeing has resumed certification flight testing of the 787 Dreamliner today," the company said in a statement.

It said four airplanes were back to "flight status" and two others "are expected to be flying again within the next week or so."

Last month Boeing said it had installed updated power system software and conducted rigorous reviews to confirm flight readiness after it was forced to halt tests due to an electrical fire that forced an emergency landing.

The company has encountered numerous difficulties in bringing the plane to market due to its use of composite materials as well as integrating production in numerous sites.

Late last year, media reports said that the first delivery of the Dreamliner to the Japanese ANA -- originally slated for February -- may be delayed until the summer, potentially threatening huge deals with other airlines.

The Dreamliners have been billed as "bringing big-jet ranges to mid-sized airplanes" that are more fuel-efficient and better for the environment.

The company has said the Dreamliner will use 20 percent less fuel than today's similarly-sized airplanes while traveling at the same top speeds.