Sunderland MP Sharon Hodgson says she will be seeking answers from Government Ministers 'as a matter of urgency' as Nissan announce it has cancelled production of its X-Trail model at the firm's Wearside plant.
And bosses say the 'uncertainty' around Brexit is not helping.
The car firm said back in 2016 that the X-Trail SUV car would be produced on Wearside after receiving assurances from the Government.
Sharon Hodgson, MP for Washington and Sunderland West, said: "I now have confirmation from Nissan UK that the new X-Trail SUV model will not be built in Washington in my constituency.
"This is a great loss of future investment in Sunderland and I am sure that many people will share my huge disappointment and concern at this news.
"Tomorrow, I will be seeking answers from Government Ministers as a matter of urgency."
Julie Elliott, MP for Sunderland Central, said: "The decision by Nissan to build its new X-Trail model in Japan rather than Sunderland – as originally planned – is devastating news for our city and the wider North East.
"Tens of thousands of people depend on Nissan for their livelihoods – both directly and through the supply chain. The production of the X-Trail would have created hundreds of much-needed extra jobs in the future.
"Sadly, any loss of future production at the plant makes it less stable. I will be doing everything I can to protect current jobs, as well as asking the government to intervene to protect the plant’s future.
"Whilst the downturn in the diesel market has been marked as one of the reasons for why this decision has been taken, we cannot deny the inevitable role that Brexit has played in this. In a letter sent to workers today, Nissan stated that continued Brexit uncertainty is not helping firms 'plan for the future'.
"The Prime Minister's deal would have only kicked the can further down the road. It was full of hopes and intentions, not plans. It did not allow businesses to plan their next few years, and this is the result of a government failure to give businesses the assurances they need, and the people the job security they deserve.
"This constant uncertainty is not conducive to encouraging business investment in this country. Brexit is now a major factor in any decisions made in manufacturing.
"Britain is getting ready to leave the EU in a matter of weeks and there is still no certainty, no assurances, and no organisation. Businesses have no idea on what terms they will be able to trade. It is not sustainable.
"It is time for the government to put the issue of Brexit back to the people, to let them decide on the future of their jobs, and the country."
In 2016, Nissan announced the next-generation X-Trail for the European market would be built on Sunderland, where a near 7,000-strong workforce already make the Qashqai, Juke, Q30, Note and the zero-emission electric Leaf.
It has been confirmed today that the X-Trail will instead be produced at its Kyushu plant in Japan.
MP Bridget Phillipson, who represents Houghton and Sunderland South, says she fears this announcement is 'only the beginning'.
She said: "Nissan’s announcement is a blow to Sunderland and to the whole north east economy.
"This is the clearest signal yet of the damage being caused to the UK car industry by the uncertainty around Brexit.
"The government’s proposed deal does nothing to end the pressure on workers and businesses, leaving all the major questions about our future trading relationship unanswered.
"I fear this announcement is only the beginning, and it is working people who will suffer the consequences.
"It need not be too late to stop this and for people to change their minds.
"I urge Theresa May to change course, and put her deal back to the public before further damage is done to this country.”
The car firm's Wearside plant produces around 2,000 cars a day and has been active since 1986.