The government's Brexit-planning ‘Yellowhammer' documents have warned that fresh food supplies will "decrease" in the event of a no-deal Brexit with long delays at crossings.
Lorries could experience delays of up to two-and-a-half days at the Dover crossing, according to the government's "reasonable worst-case planning assumptions".
This disruption at the Channel crossings could last for up to three months before seeing an improvement to 50%-70% of usual capacity.
The documents also suggest that Christmas preparations, likely to limit warehouse space, and the end of the UK growing season could exacerbate problems.
It is not predicted that there will be an "overall shortage of food", but it is expected that supplies of fresh food will decrease, choice will be limited and prices could rise.
The government has warned that panic buying could cause or exacerbate food supply.
The government was forced to publish the Operation Yellowhammer file by parliament and has sought to reduce concerns suggesting it is a working document with no-deal contingency plans continuing.
Opposition parties have responded by calling on the Prime Minister to recall parliament.