Ford has rejected claims by Donald Trump that the car maker is planning to fire all 85,000 of its U.S. employees as part of a production move to Mexico.

Ford and the Republican candidate have a long-running on-and-off spat, with the billionaire businessman bashing the company for building a plant in Mexico and moving production of its smaller cars there.

But Ford hit back at the suggestion it was planning to lay off its huge workforce in America.

'Ford has been in the United States for more than 100 years. Our home is here. We will be here forever,' company spokeswoman Christine Baker said on Thursday, according to CNN.

Trump's claims came after Ford's CEO told investors on Wednesday that it would eventually shift all North American small-car production from the U.S. to Mexico, where it is currently building a new plant.

Trump called the decision 'horrible' and the next day blasted the company on Fox News.

'Basically when they make their car, and they think they’re going to get away with this, and they fire all of their employees in the United States and...move to Mexico,' the Republican presidential candidate said.

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Donald Trump has been rebuked by Ford for claiming that the company is planning to fire it's 85,000-strong U.S. workforce

Workers at Ford's existing plant in Cuautitlan Izcalli, Mexico, in 2010

Ford has come under fire from Trump before.

Ford's new plant in Mexico, where labor is cheaper, will create 2,800 jobs in the country by 2020 according to the company

In October the presidential hopeful claimed that he had pressured the company into dropping plans to build a Mexico plant and to build them in Youngstown, Ohio instead.

'FORD LISTENED TO ME, GREAT!' he tweeted at the time.

The company in fact was going ahead with its planned Mexico site and had no plans for a Youngstown plant, it was reported.

Ford's new $1.6 billion plant opens in Mexico in 2018.

The plant in the country, where labor is cheaper, will create 2,800 jobs by 2020 according to Ford. The company said its plans will not cause any job losses in the U.S.

Still, the United Auto Workers union has called the plans 'very troubling'.

Trump was in Manhattan on Thursday to speak to The Economic Club of New York

Trump also threatened to impose import tariffs on the car maker's Mexican imports as he appeals to blue-collar workers.

'When that car comes back across the border into our country that now comes in free, we're gonna charge them a 35% tax. And you know what's gonna happen, they're never going to leave,' he said.

That would likely raise the prices of those Ford models in the U.S.

It would also appear to be a breach of the North American Free Trade Agreement, or NAFTA, which allows the United States, Canada and Mexico to trade products duty-free between themselves.

Trump has called NAFTA the 'worst trade deal in history', blaming the Clinton-era agreement for a slide in American manufacturing and shifting of domestic jobs to Mexico and other countries.

Mexico is America's third-largest trading partner, after Canada and China.

Trump would need the approval of Congress to hit Ford with a 35 per cent tax - which would be against the terms of the 22-year-old treaty.

If he tried to remove NAFTA, the unprecedented move would likely result in companies taking the U.S. government to court and higher tariff payments for American consumers, experts have warned.

However Trump has been clear that he wants to renegotiate the terms of NAFTA.

The Republican has also said that he backs government tax incentives to keep auto production in the United States, and his statements have won him support among white blue collar voters.

A CBS / New York Times poll on Thursday showed that Trump gets 58 per cent of white non-college graduates against Clinton's 32 per cent.