Patients should consider stockpiling their own drugs if it looks likely the UK will leave the EU with no deal, the pharmaceuticals industry has said, telling MPs that such a scenario could be “catastrophic” for medicine supplies and necessitate emergency powers.

Giving evidence to the Commons health committee about the possible impact of a no-deal departure on the sector, representatives from groups representing drugs producers and distributors said there was an urgent need for a Brexit agreement.

Current government contingency plans for suppliers to stockpile several weeks of drugs were insufficient, said Mike Thompson, the head of the Association of the British Pharmaceutical Industry, noting that there were no facilities at ports to store drugs at low temperatures in the event of delays.

“I think we also need to be honest with government and with parliament to say that there are more things that need to be done in a no deal and I think we’ve got to the stage of recognising that stockpiling won’t be enough and we need to put in the next phase of plans,” he said.

Martin Sawer, who leads the Healthcare Distributors Association, which represents the pharmaceutical supply chain, said patients might need to think about ensuring they had enough of their own stocks.

“We need politicians to understand that there could be consequences of a no-deal [Brexit], and those are the consequences,” he said. “We’re not suggesting anyone needs to stockpile outside of the supply chain yet, but come January that might be a different picture.

“As businesses in the supply chain, together with the government and the NHS, we have to communicate what needs to be done. We are, we believe, going to be in a difficult situation if there is not a deal by Christmas.”

Medicines supplies work to a highly sophisticated timetable, generally with twice-a-day deliveries and warehouses keeping only two or three weeks of stock, Sawer said.

“What keeps us awake at night is the uncertainty of no deal,” he said. “On average, 50% of the medicines in our depots have been through the EU before they get to the UK warehouses. And this whole integrated supply chain that we rely on was clearly set up after we joined the EU.

“It would be a catastrophic time, a ‘no deal’, for medicines supply. I’m not pulling any punches. I think we have to think of emergency powers.”

These powers, the committee was told, could include pharmacists being permitted to replace one type of drug with another without first getting the approval of a patient’s GP.

The health secretary, Matt Hancock, later told the committee he was not considering such powers. “That isn’t something that I’m aware of,” he said, insisting supplies should be maintained even in a no-deal Brexit.

“We are confident that if everybody does what they need to do, then we will have the unhindered supply,” he said.

“I am satisfied that everybody currently is doing what they need to do. Of course, there’s a huge amount more effort that’s needed between now and the end of March, should we be in a no-deal scenario, but I’m confident we can get there.”

Chris Wormald, the chief civil servant in Hancock’s department, said he agreed with this assessment but that it depended also on how France might respond with border checks in a no deal situation “which is obviously something that we don’t control”.

He said: “I’m confident that the government is doing all the right things, and if everyone does what they’re supposed to do, everything will work. That includes the uncertainty around how the French react.”