A University of South Australia scientists says genetic testing could lead to the more effective use of medication in Australian patients.

Pharmacogenetic testing or mapping a person's genetic make-up could deliver medication more effectively and save about $2.4 billion in unsafe and ineffective drug prescriptions, a scientist says.

Vijay Suppiah, a senior lecturer in pharmacy at the University of South Australia, says the testing is the most effective way to ensure patients are prescribed drugs which suit their specific DNA profile.

"Most people expect that when they get a prescription filled from a pharmacy, it will be effective and have minimal side effects," Dr Suppiah said.

"Unfortunately, that only happens in up to 60 per cent of cases"

"People don't realise their genetic makeup plays a large role in whether a specific drug will work or not."

In an article published in the Australian Journal of Primary Health, Dr Suppiah said while heavy investment into pharmacogenetic research was happening in the US and Europe, Australia was lagging far behind.

"This technology exists right now and, internationally, the testing is slowly evolving into a specialised area to guide drug selection based on genetic findings," he said.

"However, in Australia, apart from a selected few medications, such as those in oncology, most other medical specialities are yet to be involved."

An analysis by Deloitte Economics Australia suggests the testing would deliver an economic benefit of $12 billion over five years to the national health system if it was widely adopted in Australia.

"It would minimise adverse drug reactions, avoid wastage and improve quality of care for patients by enabling doctors to target the right drug and the correct dose for a patient," Dr Suppiah said.

The testing could also address issues around polypharmacy, commonly defined as the use of five or more medicines, which raises concerns, particularly for older people.

A 2018 survey of 40 elderly people in Adelaide found that almost 78 per cent used five or more medicines.

Only 17 per cent were aware of the potential interactions between their medicines and just over 37 per cent said their GP had not discussed possible side effects of their medications.

"Most participants could not describe the condition for which each medicine was prescribed, which is also very concerning," Dr Suppiah said.