Seattle  - Some 27,000 machinists at airplane giant Boeing could go on strike Friday after rejecting the company's proposed wage increases amid fears that their jobs could be shipped overseas.

The machinists, members of the International Machinists and Aerospace Workers, approved the strike action in a vote taken late Wednesday. But they 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.

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 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.

Connie Kelliher, a union spokeswoman, said: "People feel that in a time of record profits, the company should not come with any takeaways. When times were bad, workers went for years without a salary increase. But now things are good."

In a statement, Boeing said it was "disappointed" at the union's rejection of the contract proposal, which the company said would have been the aerospace industry's best package. (dpa)