Up to 300 jobs could be axed at Siemens in Lincoln as the result of a major reorganisation. Up to 190 posts will go at the gas turbine business, and about another 100 could also go over the next 18 months through "outsourcing" of activities.
It is part of plans to relocate some of the business to a new manufacturing facility in the Lincoln area.
Siemens said the decision was taken to strengthen the business and it hoped to avoid compulsory redundancies.
Sites closed
Formerly known at Alstom's, Siemens has almost 2,000 workers in the city, one of the area's largest private sector employers.
A statement from the company said: "Although we deeply regret the immediate need to reduce our workforce, we are very encouraged by the long-term outlook for the business.
"Our move to a new site in the Lincoln area will allow us to make many process and cultural changes which would be more difficult to realise in our current location."
The three locations to go are Olympic House, Firth Road and Freeman Road.
The main Pelham Bridge works site will remain but only half of that site will be used in the future.