Some people have been known to take up to 100 tablets a day, travelling from chemist to chemist to fuel their habits. Despite 2010 laws limiting the size of doses available, the reports of misuse are only increasing.

Jennifer Pilgrim, a researcher at Monash University's Department of Forensic Medicine, co-authored the new study and explained that while ibuprofen was the ingredient that caused deaths it was the codeine that created addiction.

It is for that reason experts including a senior medical adviser with the Victorian government have called for the pill to be restricted to prescription-only or for codeine to be banned from over-the-counter products. Dr Pilgrim said the other alternative was for chemists to monitor the quantity of drugs bought by each person. ''All those options involve more input from prescribers and the pharmacist, but that is the only way the situation is going to be managed,'' she said.

In one case, a 48-year-old woman who died after abusing Panafen Plus had already been identified as a doctor shopper and had restricted access to prescription medicines. But Dr Pilgrim said she was still able to travel to multiple chemists to gather large quantities of codeine.

''The coroner actually made a point of saying the problem in this case is the drugs that she can access over the counter quite easily were the ones that killed her,'' Dr Pilgrim said.