Men are being warned to not mess around with their genitals after concerns in Papua New Guinea about men injecting foreign substances into their penises to make them bigger.

Over the last two years, at least 500 men have been treated at the Port Moresby General Hospital for penile disfigurement or dysfunction as a result of injections, reports The Guardian.

"I have seen five new cases every week for the past two years and these are the ones that have come forward for treatment. We don't know how many of them are out there," said surgeon Akule Danlop.

It is said every-day substances like cooking oil, coconut oil, baby oil, and silicone are frequently being injected into men's penises, which doctors warn is extremely dangerous.

"The bulk of them have abnormal, lumpy masses growing over the penis and sometimes involving the scrotum," said Danlop.

He said the men come from different demographics, "including teenagers, middle-aged men, and lawyers".

It has also prompted a study into why such a big number of men are trying to enlarge their penises, and if there is any connection to pornography viewing.

But it's not only Papua New Guinea struggling with DIY penis enlargers.

In 2016, the BBC reported that English doctors were having to treat men who had infections as the result of trying to make their penises bigger at home or with the help of untrained assistants.

Newshub.