A cheese processing firm employing 140 people has warned jobs could be at risk if Brexit trade talks end without a deal.
Prima Cheese in Seaham, County Durham, buys the majority of its ingredients from the European Union and said tariffs would damage its business.
The company fears customers “can’t take” higher costs.
With the Brexit transition period ending in five weeks, the UK government said negotiations with the EU continue.
Prima blends and shreds hundreds of tonnes of cheese each week, with 90% of its raw materials coming from Europe.
Director Nima Beni said: “Mozzarella cheese, at the moment, is around £2.60 per kilogram. With World Trade Organisation tariffs you’re then looking at £1.84 on top of that, which is massive.
“We’re talking about an extra cost – a cost I feel our customers can’t take.
“This year, Covid shows the world has to work with each other rather than against each other. More time is needed to get things in place.”
Deliveries from the likes of Denmark currently require relatively little customs paperwork, the firm said, but it is worried that situation will change from January.
A quarter of its sales come from exports outside the EU and commercial director Nagma Ebanks-Beni believes a lack of trade agreements with countries around the world has left them “in limbo”.
“From January with exports to countries like Hong Kong or Singapore or Dubai, we are unsure how to be handling the documentation.
“If we see a reduction in sales it will impact jobs.”
Julie Underwood, of the North East Chamber of Commerce, warned firms will see “a huge amount of change” whether or not a post-Brexit deal is struck.
The government said ministers were “working hard to find a solution that respects British sovereignty” but could not promise an agreement would be reached.