According to the Financial Times, the Cabinet was briefed on plans for alternative options if new customs controls cause problems on the Dover-Calais route.
Transport Secretary Chris Grayling raised the possibility of hiring entire vessels, or securing space in ships, to get food, medicines and other supplies in through alternative ports, the newspaper said.
When asked about the claims, a Department for Transport spokesman said: “We remain confident of reaching an agreement with the EU, but it is only sensible for government and industry to prepare for a range of scenarios.
“We are continuing to work closely with partners on contingency plans to ensure that trade can continue to move as freely as possible between the UK and Europe.”
Pro-EU Labour MP David Lammy said: “Brexit has become like a declaration of war on ourselves.
“Emergency ships will be chartered for food and medicine if we leave the EU with no deal.
“But at least when we’re using ration books and running out of drugs, we’ll have taken back control.”
At Tuesday’s Cabinet meeting, Prime Minister Theresa May ordered ministers to present weekly updates on Brexit preparations for leaving with a deal and without.
Brexit Secretary Dominic Raab will deliver the updates – and he told those gathered that “good progress” was being made on preparing for both outcomes.
Mrs May said preparations for ‘no-deal’ remain “essential”, but stressed the government was focused on getting a deal.
Meanwhile, the PM will face her backbenchers at a potentially crucial meeting on Wednesday.
Mrs May will address the 1922 committee of Conservative MPs, amid speculation she could be about to face a vote of no confidence in her leadership.