The head of the NHS in England has said he is “really worried” about medicine supply issues.

A number of experts have raised concerns about cost implications and supply disruption linked to the war in Iran.

The NHS England chief executive, Jim Mackey, was asked during a phone-in on LBC Radio on Tuesday what contingency planning was in place because “the UK imports 75% of its medicine”. He said: “We are really worried about this. We’ve already had a couple of supply shocks in the last 12 to 18 months of key supplies.”

He said a team was in place to “focus on where the risks might be through the supply chains”.

Asked how much supply there was, he replied: “It depends what you’re talking about. In every area, we’ve got enough to get through for a reasonable period … so generally, a few weeks.

“Because things perish and it costs money to store and various other things go out of use, you can’t hold years and years of supply. Generally, dependent on the product, we keep a reasonable period. Some of that is held centrally, some held locally.”

Questioned whether, in some instances, it would be “weeks’ worth of supply”, Mackey said: “Yeah, it could be days for some products.”

His remarks surprised drug and pharmacy organisations, which said they were not yet seeing any shortages related to the conflict.

One industry source, speaking anonymously, said: “What he was saying doesn’t tally with the situation on the ground at the moment. Everyone’s worried but no one is saying that stuff isn’t coming in.”

Henry Gregg, the chief executive of the National Pharmacy Association, said: “We’re not currently seeing shortages of medicine directly linked to the conflict in the Middle East, but pharmacies are seeing disturbing spikes in prices, which can be an early indicator of challenges.

“The Department of Health have issued unprecedented numbers of price concessions designed to cope with price surges, which are likely exacerbated by this current situation.”

Price concessions are when the Department of Health and Social Care lets the NHS pay more than usual for certain drugs as a temporary measure to circumvent a supply problem and ensure stocks keep arriving.

Some drug prices have risen recently as a result of shortages of key ingredients and disruption to manufacturing processes, including firms switching production to new factories.

A spokesperson for the Association of the British Pharmaceutical Industry, which represents manufacturers of branded medicines, said: “We are not aware of any supply issues resulting from the conflict in Iran. The region is not a significant exporter of medicines, and supply routes are flexible and can adapt to disruptions. However, we will continue to monitor this, as we do with other potential supply risks.”

One industry source stressed that most generic drugs, which the NHS obtains from China and India, do not pass through the strait of Hormuz, a major flashpoint in the US and Israel’s war with Iran, and therefore disruption there is unlikely to have an immediate impact on supply.

But another said: “The current conflict in the Middle East isn’t having an impact on the supply of branded medicines into the UK. This is because relatively little medicine manufacturing takes place in the region, so the main risk is disruption to shipping routes rather than production itself.”

The NHS and pharmacies are already dealing with a country-wide shortage of aspirin and co-codamol, a strong painkiller. Supplies of HRT and drugs to treat ADHD and epilepsy have also been unreliable in recent years.

A government spokesperson said: “There are currently no reported medicine shortages as a result of conflict in the Middle East. We continue to monitor the situation closely for any impacts on the medical supply chain.

“The department actively monitors emerging threats to supply resilience and has established processes in place to manage disruption across the health and social care sector.”