The highly contagious norovirus has recently struck some 20 Australians who were out in New Zealand for a skiing holiday.

Between August and September, the Australians were infected of the virus after drinking allegedly contaminated water in Cardrona town, 40km northeast of Queenstown.

Dr Derek Bell, Public Health South medical officer of health, told AAP that some of the affected Australians were able to recover while still in New Zealand, while others came back home still ill. And that it was only after their arrival back home that Public Health South was informed of their predicament. Public Health South said it took no time to contact the still sick skiers in Australia.

An easily spreadable viral gastroenteritis, infection of the norovirus leads to nausea, diarrhoea, vomiting and abdominal pain.

Cardrona, before the group's arrival, had actually put in place a "boil water policy," following the contamination of its drinking water supply by waste water.

Before their arrival, the outbreak is actually already under control in Cardrona, Public Health South said.

From August 18 up to September 5, there have been 53 reported cases of norovirus in Cardrona, according to the AAP. It could not be determined from which states the affected Australians came from.

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