Antibiotics resistance is quickly becoming a global burden, most recently leading to a common urinary tract infection drug no longer working.
Now there are concerns some sexually transmitted infections will no longer be able to be treated.
General Practice NZ chairman Dr Bryan Betty told AM on Tuesday that bacteria treated by antibiotics over time can develop the ability to resist the drug that is designed to kill them.
"We're seeing this worldwide now on a number of conditions, it's becoming a real concern and in particular with sexually transmitted diseases."
Gonorrhea is of particular concern for resisting antibiotics, he said, noting that overseas we're seeing cases of gonorrhea being resistant to all types of antibiotics.
Betty said gonorrhea is "a severe disease" transmitted through unprotected sex and can cause long-term problems, including chronic pelvic pain, infertility and severe eye infections in newborn babies.
Betty explained how overuse is what's driving this resistance.
"If we're using up this very, very precious resource of antibiotic through overuse then we do potentially have a major problem down the track in terms of how we treat this going forward.
"What we've seen over the last few decades is the overuse of the antibiotics, really in two places - one in medicine where antibiotics are prescribed inappropriately to patients, that is patients who shouldn't have them having them, and secondary in the environment, so the treatment with antibiotics with animals for instance."
Betty said about 85 tonnes of antibiotics are used in the treatment of animals in New Zealand every year and most of that ends up in the environment.
"What we're seeing worldwide through antibiotic resistance across a range of different diseases, it's estimated at the moment about 4.5 million people worldwide die per year from diseases that cannot now be treated by antibiotics," he said.
"That is thought to increase to about 10 million in the next 20 years so this is a very serious problem."
