Sewage contaminating a creek running through a Nelson campground is thought to be responsible for a suspected outbreak of the stomach bug norovirus.

The Golden Bay Holiday Park remained closed today after holidaymakers became sick on Saturday night. Most campers left during the weekend, and a health protection officer was to reassess the situation today, the Nelson Mail reported.

Routine water quality testing by Tasman District Council staff on January 15 found high levels of E.coli contamination at the mouth of the Tukurua Stream, which runs through the campground.

The level was 700 most probable number (mpn), well above the 240mpn which would see the council start "intensive monitoring".

Council environment planning officer Dennis Bush-King said the council had been working on tracing where the contamination entered the creek and the results should be known today.