There were 200 medicine shortages listed with the administration between January and August. In the coming months that figure is set to eclipse the 224 recorded for 2017, and the 196 noted in 2016.

Thousands of Australian women are currently affected by a nationwide shortage of one of the country's main contraceptive pills, Norimin-1, with new supply not expected for several weeks.

The Norimin-1 shortage was first listed with the TGA on September 6, with the contraceptive pill expected to be available to patients by October 9.

A Therapeutic Goods Administration spokeswoman said issues with overseas pharmaceutical companies are often to blame.

"The problem of medicine shortages is not unique to Australia and in many situations shortages are unable to be avoided," the spokeswoman said.

"Potential reasons for medicine shortages can include commercial decisions, logistical difficulties, recalls, manufacturing issues and unexpected increases in demand."

While pharmaceutical companies were not required to report medicine shortages to the authority, reporting will be made mandatory from January 1, 2019 after legislation was passed by the federal government last week.

The mandatory reporting will apply to all prescription drugs and some over-the-counter medicines.

"The scheme will not prevent shortages but will enable early identification and improve the ability of the TGA, sponsors, doctors and pharmacists to respond and minimise the impact on Australian patients," the spokeswoman said.

The legislation came about following round table discussions with medical experts.

Australian Medical Association president Tony Bartone said medicine shortages have become more common over the past year.

"When you're part of a global supply chain, when an interruption happens in an overseas plant, it has far-reaching consequences," Dr Bartone said.

"The new legislation means there's a requirement on distributors and supplies and big pharma to give better visibility and notification of impending shortages.

"We'll haver better awareness about the logistical supply, and when there's an interruption of it, it would allow for appropriate alternatives to be made available."

The shortage of popular contraceptive pill Norimin has sparked warnings for women to look for altenatives to prevent unwanted pregnancies.

Thousands of women are affected by the shortage with new supply not expected for several weeks.

"The TGA is aware that a generic product for Norimin-1, called Brevinor -1 which contains the same dose of active ingredients, is being supplied," the TGA spokeswoman said.

One Canberra pharmacy reported people coming as far away as Sydney to fill their prescriptions due to the shortage.

Several pharmacies contacted by Fairfax Media in Sydney, Melbourne and Canberra said they were affected and would not receive new stock until mid-October.

Medical director of Family Planning NSW Dr Deborah Bateson said while it's not known how many women use Norimin-1, its listing on the pharmaceutical benefits scheme meant it's one of the most common contraceptives.

She said it can be difficult for women using contraceptive pills to find another brand during shortages due to their different make-up.

"People need to know in advance so they're not left without pills and not being able to fill prescriptions," Dr Bateson said.

"The main thing is that there's alternatives available but what we don't want is for people to stop taking the pill and have an unintended pregnancy."

Prominent gynaecologist and obsetrician associate professor Gino Pecoraro said the increasing instances of medication shortages is particularly concerning when it came to contraceptive pills.

"If patients are running out, the first thing they should do is go and see if there's a different branded contraceptive with the same levels of hormones and medication," he said.

"A good thing to do is speak to your GP about how the shortage would affect them and what other alternatives are available."