Researchers, carrying out a study at University of Otago, have stated that “it's only a matter of time before imported medicines have nasty or possibly fatal consequences in New Zealand”.

The team of researchers from the University found that some of the drugs contained amounts of medicine significantly different than what is stated on the packet, while some contained an entirely different drug with strikingly different compositions.

Professor Pauline Norris from Otago University's School Of Pharmacy states, “We really think people should not buy medicines over the net, some of these websites are designed to look really professional and reassuring... but you don't know where the company is and you don't know where the products are going to come from”.

Health authorities warn that “dangerous reactions and possibly death will result from an influx of internet-order medicines containing everything from arsenic to bird droppings”.

The warning comes as medicines and therapeutic products intercepted at New Zealand's border have increased rapidly in recent years.

Medsafe, New Zealand Medicines and Medical Devices Safety Authority, which provides information on medicines and medical devices in New Zealand, says while it is able to stop most of the illegal medicines at the border, there are some that still manage to seep through.