GS Yuasa Corp, the Japanese maker of lithium-ion battery cells used in Boeing Co's 787 Dreamliner, said it is working closely with the U.S. company, lead battery contractor Thales SA of France and regulators to get the 787 back into the air.

Its statement comes after a report in the Wall Street Journal on Thursday said the company disagreed with Boeing about what should be included in a package of measures aimed at getting the airliner back in the air.

"Workers involved in design, production and quality control are working 24 hours a day using all their technical skill and knowledge to uncover the cause and make the battery safer," GS Yuasa said.

One battery caught fire onboard a Japan Airlines Co plane in Boston while another forced an All Nippon Airways Co plane to make an emergency landing in western Japan in January, prompting regulators in the U.S., Japan and elsewhere to ground all 50 Dreamliners in operation.