A popular Golden Bay camping ground has been closed and its campers quarantined on site after an outbreak of norovirus.

A Nelson health inspector visited the Golden Bay Holiday Park at Tukurua Beach in the Tasman district on Wednesday, finding the campground's facilities overwhelmed by up to 50 new cases of sickness in the camp, the Nelson Mail reported.

Norovirus is a gastroenteritis bug that causes diarrhoea and vomiting.

About 60 per cent of campers had experienced illness in the past week.

The campsite's owners had been advised to keep the site closed until the last person was clear of symptoms for 48 hours, Nelson Marlborough medical officer of health Ed Kiddle said.

The cause of the outbreak was not known but the virus could spread through water, Dr Kiddle said.