GM has voiced concerns over the potential impact of the United Auto Workers’ (UAW) proposals on its long term interests, Reuters reported.

The UAW wants a 40% wage increase over the four year contract with an initial 20% raise upon ratification. According to the news agency, this was due to CEOs of the Detroit Three having won 40% pay rises on average over the last four years.

It was also pushing for shorter work weeks, permanent status for temporary workers and improved benefits, including defined pensions for all employees.

In addition, it wants to restore retiree health care benefits and cost of living adjustments in what UAW president Shawn Fain described as its “most audacious and ambitious” proposal in decades.

GM said the new demands “would threaten our ability to do what's right for the long term benefit of the team.

“We think it's important to protect US manufacturing and jobs in an industry that is dominated by non unionised competition,” the company added.

The UAW had yet to comment at publication time.