A fourth person has died from listeria contracted from eating contaminated rockmelons, Victorian health authorities have confirmed.

The latest death means two people from NSW and two from Victoria have been killed by the outbreak, linked to a farm in southern NSW.

The ABC understands the latest listeriosis victim died more than a week ago but the cause of death was only confirmed on Tuesday.

“This latest case has only just been linked to the outbreak as a result of our microbiological testing,” Victoria’s deputy chief health officer Dr Brett Sutton said.

There are now 17 confirmed cases of listeriosis around the country linked to the contaminated rockmelons.

Dr Sutton said six of those cases were in Victoria – three men and three women, aged between 60 and 90.

Cases have also been reported in Tasmania and Queensland.

The infection starts with flu-like symptoms such as fever, chills, muscle aches, nausea and sometimes diarrhoea.

The NSW Food Authority confirmed last week that investigations into the deadly outbreak began in January.

The fruit has been pulled from supermarket shelves across the country as a result.