Almost half of employees at Cooper Tire Europe in Melksham could lose their jobs.
The company could end its production of light vehicle tyres and instead, get such tyres from global manufacturers.
This could result in 300 jobs out of 732 becoming redundant over the next 10 months.
Cooper Tire Europe says its headquarters will remain in Melksham as will sales and marketing offices, Europe Technical Centre and materials business.
Cooper tires is Melksham's biggest employer making tyres for cars, motorbikes and racing cars.
Unite the union say the jobs earmarked for redundancy are in the car tyre side of business which has been 'hit by the dumping of cheap inferior tyres from countries such as China.'
Tony Hulbert is Unite's regional officer.