It has been announced workers at the Jaguar Land Rover plant in Castle Bromwich, Birmingham, are moving to a three-day week until Christmas.
It is unclear how many people will be affected by the change with initial numbers reported between 1,000 and 3,000 workers.
Jack Dromey MP for Birmingham Erdington blamed the changes due to "a combination of Brexit chaos and mishandling by ministers of the transition from diesel."
In a statement regarding Castle Bromwich, Jaguar Land Rover said: “As is standard business practice, Jaguar Land Rover regularly reviews its production schedules to ensure market demand is balanced globally.
“In light of the continuing headwinds impacting the car industry, we are making some temporary adjustments to our production schedules at Castle Bromwich.
“We are, however, continuing to over-proportionally invest in new products and technologies, and are committed to our UK plants, in which we have invested more than £4 billion since 2010 to future proof manufacturing technologies to deliver new models."
The move came hours after former shadow minister Sir Bernard Jenkin accused Professor Dr Ralf Speth of scaremongering over a prediction that crashing out of the EU would have a “horrifying” effect on the leading automotive firm’s business.
Professor Speth had told the UK’s first Zero Emission Vehicle Summit in Birmingham last week – attended by the Prime Minister – that a hard Brexit could result in the “worst of times” for the UK while the cost to Jaguar Land Rover would be more than £1.2 billion a year.
Asked his view on the German businessman’s warning on Monday, Sir Bernard, a member of the Eurosceptic European Research Group, told BBC Radio 4’s Today: “I’m afraid I think he’s making it up.
“We’ve had figures made up all the time by the scaremongers in this debate and I’m afraid nobody believes them.”
The comments sparked criticism from Labour and from within the Harwich and North Essex MP’s own party.
Mr Dromey described Prof Speth as “the man … who has transformed (Jaguar Land Rover) into a world-class success story, doubling the company in size to over 40,000”, adding: “The irrational zeal of the #Brexiteers is breathtaking!”
Sir Bernard’s comments were described as “embarrassing” by pro-Remain Tory MP Anna Soubry.
Unite assistant general secretary Tony Burke said: “This is the continuing effect of the chaotic mismanagement of the Brexit negotiations by the government which has created uncertainty across the UK’s automotive industry and the manufacturing sector generally.
“It is also the result of the mishandling of how the UK makes a just transition from diesel and combustion engines to electric vehicles. Both issues have damaged the ‘jewel in the crown’ of UK manufacturing – our automotive industry.
“The situation is not helped when you have arch-Brexiteer MP Sir Bernard Jenkin accusing Ralf Speth of ‘making it up’ when it comes to Brexit and the car industry."