Some 1,200 security guards have been confined to their hotel rooms in an attempt to stop the spread of the virus and have been replaced with soldiers.
The alarm was raised when security workers complained of headaches, vomiting and diarrhoea. Thirty-two people including three foreigners have been quarantined for treatment. Local and national health officials say they have tested 1,023 people.
Military personnel have been deployed to replace sick security workers at 20 venues. The games will officially open on 9 February.
Some of the security workers had also been working at the athletes' village, raising fears that the virus could make its way to competitors.
Officials were conducting an epidemiological survey to track the spread of the virus. A preliminary five-day survey of water for cooking and drinking showed no signs of norovirus. Restaurants and all food facilities linked to the Olympics were also being investigated.
Local media reported that symptoms were first noticed on 31 January, not 4 February as organisers have claimed, and have criticised what they consider the slow response of authorities. There have also been complaints about the quality and cleanliness of accommodation and restaurants.
There have also been concerns over the below-freezing temperatures being reported in Pyeongchang. Temperatures for the opening ceremony are expected to be -10C. In rehearsals for the opening ceremony, wind chill brought the temperature down to -23C.
British team bosses have advised athletes not to attend if they are due to compete within 48 hours of the three-hour ceremony.
A special bag with hot packs, seat-warmers, a blanket, a hat and a windbreaker will be distributed to spectators at the opening ceremony.
Organisers are desperate for the games to go off without a hitch. There is added pressure this year as they host a North Korean delegation in a move that represents a thaw in relations between the two countries following a period of high tension on the Korean peninsula.