Six people have now died in a rockmelon-related listeria outbreak.

Nineteen people have been infected during the outbreak – linked to a single NSW farm – including the fatal infections of three Victorians and three from New South Wales.

Rombola Family Farms in the NSW Riverina region halted production of potentially contaminated melon types on February 23 after it was identified as the source of the infection.

Affected produce has reportedly been withdrawn from sale and distribution.

Dr Vicky Sheppeard, communicable diseases director at NSW Health, says those infected may not show symptoms for up to 70 days, so it is possible that more listeria cases will surface.

But the health department says there is no risk of contracting the disease from rockmelons currently on sale.

“It is important to know that people fall ill with listeriosis every year but most of the cases are never related to an outbreak like we are seeing. Sadly, up to one-third of those who do contract the disease will die,” Dr Sheppeard said.