An expiry date mix-up has prompted an alert over a batch of EpiPens, which thousands of people carry for the emergency treatment of life-threatening anaphylaxis.

On Wednesday, Australians carrying EpiPens, and carers of people who need them, were urged by health authorities to check the expiry dates on the injections because of a recently discovered labelling problem.

Thousands of people carry EpiPens to treat anaphylaxis. Credit:Getty Images

Alphapharm, a company that distributes the medicine, said a small number of reports from pharmacies in Victoria had revealed the expiry date on the pens did not match the expiry dates on cartons they were packed in.

A spokeswoman for the company said she did no know of any cases where the discrepancy had caused harm to people. She said the reports of questionable products had come from a particular area of Victoria but she would not reveal the location. The spokeswoman said the expiry date on the pen was the correct date, not the expiry date on the carton.