A bottle of sleeping pills from the mid 1960s is the leader in a competition to find Australia's oldest medicine still being kept at home.

Pharmacist Hany Aita from Broken Hill in far-west New South Wales said a resident gave one of his staff the bottles of pills a few months ago.

Mr Aita took a photo and entered it in the Search for Australia's Oldest Medicine competition run by the not-for-profit group Return Unwanted Medicines (RUM) and the Australian Journal of Pharmacy.

There have been 22 entries since the competition began last week, and each fortnight until the end of September the pharmacy that collects the oldest medicine will win a ticket to a pharmacy conference.

Mr Aita said it was the oldest medication he had come across since he graduated 13 years ago.

"Most of the time we will get things a few years old. Before this one, the oldest I have seen was 1985, I think," Mr Aita said.

"I just thought it was really very unique … and I was really fascinated by the information on the label. You don't normally see a dispensed label that old.

"I just had a feeling [to] keep it as some sort of souvenir or something like that, so I'm just keeping it here safe in the pharmacy."

One of the bottles was dispensed in 1964, the other in 1965, and one was labelled as containing Nembutal, which is pentobarbitone, also used as an assisted dying drug.

Pharmacist Hany Aita urges customers to give old medication to their local pharmacy so that it can be discarded safely. ( ABC News: Sofie Wainwright )

Mr Aita said he was glad the competition raised awareness about the importance of safely discarding unwanted and expired medicine.

"If you have anything at home that you're not using or any old medication, whether it's prescription or non-prescription, you can take it to your local pharmacy and it can be discarded in a safe way."

Toni Riley from the RUM Project told the ABC earlier this month that out-of-date and no-longer-required pharmaceuticals were dangerous.

"The ingredients may not be active, so they might be ineffective or could potentially make you sick," Ms Riley said.

She said medicines should not be flushed down the sink or toilet or thrown into the household bin, because they could end up in landfill and waterways and could damage the environment.

The RUM Project's website said more than 742,000 kilograms of medication was collected across Australia between July 2016 and June 2017.