At 10pm last night, warehouse workers and drivers at the Cheshire NHS Logistics centre started the first of two 24-hour strikes in protest at work being transferred to German-owned delivery giant DHL.
The second 24-hour stoppage is scheduled to take place next Tuesday, to coincide with a debate on the health service at the Labour Party conference.
The Runcorn plant is one of five in the country that supply hospitals, GP surgeries and clinics with health equipment.
It sources and delivers goods from bedpans to food to all health centres in the North West.
Frank Hont, North West regional secretary of health service union Unison, said: "Our members in Runcorn are angry, upset and disappointed. These are people who have never taken industrial action in their lives and who don't take industrial action lightly.
"Many have worked for the NHS all their lives and see themselves as a part of the NHS.
"The only way we can continue to maintain the health service is by continuing to work together and we have no idea what changes DHL would introduce.
"It is a very efficient and effective service which is partly why it is so incomprehensible that this has happened."
Workers voted last week to take industrial action after the Government confirmed the transfer of their jobs to DHL in a 10-year contract which Unison said was worth £3.7bn.
Karen Jennings, the union's head of health said: "Members have worked hard to build NHS Logistics into an award-winning service and don't deserve to be treated this way. There is simply no logical explanation for this transfer."
Unison said it would draw up emergency plans, but warned that the strike will have an immediate impact on hospital supplies.
Mr Hont said: "Hospitals and surgeries do not hold huge supplies so this will have an immediate impact and if strike action continues it will have an effect on supplies.
"We're taking industrial action to bring this issue to the attention of the public, who ultimately will suffer if this part of the NHS is privatised."
Officials warned that hospitals across England will quickly run out of bulky items such as bedpans and will run short of hand gel, latex gloves and food.