Grampians Health public health expert Rob Grenfell is urging families to be particularly careful in a season often marked by gastro, both viral and bacterial.

While there has been no official warning from Victoria's health department on gastroenteritis, Australian Community Media has been hearing anecdotally of a rise in cases among school-aged children.

Dr Grenfell said this was a standard virus that tended to pick up when children were playing together more, such as at Christmas time.

He also warned this could be a worrying season for bacterial-based gastro with people urged to socialise and eat outside more amid a community-wide COVID-19 flare-up.

"Food-borne gastro can be prevalent when food is sitting around in the heat," Dr Grenfell said.

"As we move into warmer weather, refrigerate.

"If you think food has been out a little while, don't eat it."

For an infectious gastro, the best prevention is good, soapy hand-washing - especially after going to the toilet and before eating.

This is a factor Dr Grenfell has encouraged everyone continue to make a habit in preventing against COVID-19 spread.

Unlike coronavirus, hand sanitiser is not effective in protecting against spreading gastro, Victoria's Better Health Channel says.

Gastro can spread quickly and is usually spread by food or drink.

It is a bowel infection that causes diarrhoea and sometimes vomiting.

Dehydration is a key side effect from gastro and can be particularly dangerous in young children.

Other tips to prevent against gastro this holiday season are to keep toilets and bathrooms clean and disinfected.

For those cooking, do not handle raw and cooked foods with the same implements or on the same surfaces unless these have been thoroughly washed between uses.