With the Production Tax Credit (PTC) on renewable energy set to expire at the end of the year, Vestas Wind Systems A/S had previously said it could be forced to lay off a total of 1,600 employees in North America if the scheme is not renewed.

Vestas, which is battling the effects of government austerity measures in various countries, said the 800 staff cuts so far this year represented 20 percent of its North American workforce.

"The U.S. wind industry has slowed, largely due to the uncertainty surrounding the Federal Production Tax Credit extension," said Martha Wyrsch, head of Vestas-American Wind Technology, Inc.

Rising costs and fierce competition, especially from Asian rivals, have added to its problems.

Vestas has already closed a number of factories worldwide and will transfer sales staff from southern Europe to South America.

The group told analysts and investors in briefings on Wednesday it would stop non-profitable projects as it battles worsening prospects, aiming to lift its operating margin to high single-digits in the medium term.

The group plans to shift focus increasingly to emerging markets in a bid to regain growth and offset cooling demand in mature Europe and United States markets.

The company's order intake in the first half of the year was 24 percent down on the corresponding period a year earlier.

Vestas shares, which have plummeted from a peak of around 700 crowns set in 2008, traded down 1 percent at 34.65 crowns by 1023 GMT (0623 ET) against a 0.5 percent decline in the Copenhagen stock exchange's benchmark index <.OMXC20>.

(Reporting by Mette Fraende; Editing by Mark Potter abnd Mike Nesbit)