Three Australians have died after eating melon contaminated with listeria.

The outbreak has been linked to a fruit farm in New South Wales - and officials are urging pregnant women, the elderly and anyone with serious conditions such as diabetes and cancer to throw away pre-cut rockmelon.

Listeria is a commonly found bacteria, and although most people do not fall ill after eating contaminated foods, it poses a serious threat to the vulnerable.

At least 15 cases of listeriosis have emerged since the outbreak began last month - and further cases are expected to emerge because symptoms can take six weeks to develop.

Dr Vicky Sheppeard, from New South Wales Health, said: "All 15 cases are elderly people, and most of them have significant underlying health conditions.


"We can confirm that 13 of the 15 cases consumed rockmelon before the onset of their illness. People vulnerable to listeriosis should discard any rockmelon purchased before 1 March."

NSW issued listeria outbreak alert as soon as rockmelon proved the culprit thanks to NSW Health’s robust outbreak procedures #nswpol https://t.co/9YHztyYP86 pic.twitter.com/aKXvj3bzsM — NSW Health (@NSWHealth) March 3, 2018

Listeriosis begins with flu-like symptoms including chills, fever and muscle aches.

The public has been assured that all contaminated melons have now been taken off supermarket shelves.

Listeriosis begins with flu-like symptoms including chills, fever and muscle aches and can take up to six weeks to show symptoms.

Other foods that can pose a risk of listeriosis include cold salads, raw seafood and unpasteurised milk products.

A deadly outbreak in South Africa has killed more than 170 people since January last year.