NSW hospital data reveals rotavirus - a common cause of Gastroenteritis - cases increased almost 400 per cent in January, 2023.

Symptoms can take up to three days to recover, and include nausea, vomiting, diarrhoea, fever, abdominal pain, headache and muscle aches. Infants and toddlers are among the most vulnerable.

A spokesperson for the Western NSW Local Health District told the CWD localised data for Orange and surrounds is not currently available.

Residents are urged to stay on high alert, keep sick children at home, wash hands and surfaces thoroughly, and wear gloves when cleaning bodily fluid.

"The message to the community is clear - simple measures can help stop the spread of gastro," Director of NSW Health's One Health branch Keira Glasgow said.

Maintaining good hand hygiene and keeping children at home when they are unwell will give us a good chance to slow the spread before February, when children will all be back together at school."

The main treatment for viral gastroenteritis is to rest and drink plenty of fluids, the statement said. Most people recover without complications.

Immunisation is recommended and part of the childhood immunisation schedule. Immunisation is free for children under six months of age.