Health officials said five members of the security workforce called in sick today with symptoms of the bug, which causes sickness and diarrhoea.
No athletes or team officials have been taken ill so far.
A temporary toilet facility has been shut at the village in Glasgow's east end where athletes began arriving this week.
The Games opening ceremony takes place on Wednesday at Celtic Park.
Gillian Penrice, consultant in public health medicine for NHS Greater Glasgow and Clyde, said: "As we would expect, the number of new cases is continuing to decline.
"Staff who have been symptom-free for 48 hours are starting to return to work and those who are still experiencing mild symptoms are not giving any cause for concern as a result of the virus.
"Norovirus is the most common stomach bug in the UK and is usually mild and generally lasts for 24 hours.
"Village residents and workforce have been informed and issued with health information and we continue to monitor the situation closely."
The five workers who reported they were unable to work today have been told to remain at home until they have been clear of symptoms for 48 hours.
The health board's Public Health Protection Unit, Health Protection Scotland and environmental health officers from Glasgow City Council are working with Games organisers and contractors to investigate, monitor and contain the incident.
First Minister Alex Salmond said yesterday that Games organisers were confident they had identified the probable source of the outbreak, a temporary facility in use during construction work in the security area.
Mr Salmond said: ''We're confident we've identified the cause of the outbreak, a temporary facility which was not as it should be.
''We've taken the measures necessary. We've got a terrific health service and they are on the job. 'We are confident that we're getting to grips with the cause. We will see more cases but it will tail off over the next few days.''