The suggestion comes from a University of Otago survey of 265 community pharmacists throughout the country on their disposal practices for unused or expired medicines.
More than 90% of the respondents wanted a state-run disposal and destruction system.
However, when Pharmac was asked about the issue, it referred the Otago Daily Times to the Ministry of Health.
In its response, the ministry acknowledged the importance of the proper disposal of pharmaceutical waste.
"Although there are currently no national guidelines for the disposal of unused medications, we expect community pharmacies to dispose of them with due care," it stated.
The survey showed that while in most instances solid and semi-solid medications were removed by contractors for destruction, unwanted liquid and class B controlled drugs often went down the pharmacy sink or the toilet.
One of the researchers, school of pharmacy lecturer Dr Rhiannon Braund said the Otago area was one of the few where all community pharmacies' unwanted medicines were collected and disposed of by the district health board at its expense.
People who have unwanted medicines in their homes are advised to take them back to their pharmacy for collection.
District health boards have agreements with community pharmacies which include the disposal of medicines, but these agreements vary.
A paper published in the Journal of Primary Health Care on the survey said while some pharmacies reported it was a rare occurrence for class B controlled drugs to be returned, it was not unheard of.
It cited the 2007 instance of a bag of medications worth $14,500 being returned to a Dunedin pharmacy with its contents including oxycodone and morphine.
The survey did not identify the specific types of medication being disposed of.
The message from pharmacists was that they wanted consistency across the country as what was happening at the moment was "so haphazard".
The school of pharmacy has also undertaken research on the environmental effect of drug disposal by testing the water around Dunedin sewage outfalls.
The data on this has yet to be fully analysed and it was hoped comparisons with data in Auckland and the Waikato would be possible, she said.
Dr Braund said other research showed that much of the medication prescribed to people was either not used correctly or not used at all, lessening its effectiveness and increasing waste.
In some areas, pharmacists were paid through district health boards to undertake medicine use reviews, particularly for those patients using multiple medicines.
This involved specially trained pharmacists discussing medications with patients in a consultation, helping them to understand what they were for and how they should be taken.
It was a service designed to complement that of the prescriber.
Pharmacists were not trying to establish themselves as "mini doctors" diagnosing patients, but as experts in medicines they were keen to work with GPs to help patients understand their medications better.
Medicine use reviews were not funded in the Southern District Health Board area yet, she said.
