Seattle - Some 27,000 machinists at airplane giant Boeing are to go on strike at 12:01 am Pacific time Saturday (0700 GMT) after extended talks failed and its largest union again rejected the company's proposed wage increases amid fears that their jobs could be shipped overseas.

"Despite meeting late into the night and throughout the day, continued contract talks with the Boeing company did not address our issues,'' the International Association of Machinists and Aerospace Workers said in an online statement.

The machinists approved the strike action in a vote taken late Wednesday but delayed implementing the strike after the company reopened negotiations with union leaders, who gave Boeing until Friday evening to provide an "exceptional contract offer" under the guidance of a federal mediator.

Boeing's contract offer included a signing bonus of 2,500 dollars, an 11 per cent raise over three years with an additional lump sum payment in the first year, and, a 14 per cent increase to monthly pension plans, among other benefits.

There are no additional talks scheduled.

Union leaders said that more than 80 per cent of workers voted for the strike and 87 per cent supported a walkout. They are demanding higher wages and benefits, and assurances that the company will not shift manufacturing jobs overseas.

The union represents about 27,000 employees in Washington state, Oregon and Kansas who make parts and assemble planes for Chicago-based Boeing.

The dispute comes as Boeing's factories are running at full-tilt to keep up with the strong demand for the fuel-efficient 787 Dreamliner. The company has orders for 900 of the planes, but production is already running two years behind schedule.

According to the Wall Street Journal, the strike could cost the company 100 million dollars a day in lost revenues. (dpa)