A "few thousand" people dining in corporate comfort at the All Blacks-Ireland test at Eden Park last Saturday could have been struck down with gastroenteritis.
A week after the big match, public health officials have yet to pinpoint the exact cause for the outbreak that left at least 100 patrons
who dined in four separate corporate hospitality areas reeling from a suspected norovirus infection.
"There was one kitchen from which everyone was served ... but it's likely there were a range of sources for the food," said Auckland Regional Public Health Service's Dr Julia Peters.
More than half of 200 people interviewed so far have reported illness.
Dr Peters did not know how many people could have been affected but had been told it could have been a few thousand.
Murray Reade, Eden Park Trust Board's general manager, said the board had been in "some pretty close dialogue" with its caterer, Michael O'Brien Catering.
"We're obviously deeply concerned about this issue, and Michael O'Brien Catering being our caterer certainly have come under a lot of scrutiny from the trust board over this incident."
Eden Park's caterer of 18 months is an Australian company which lists among its clients the Optus Oval Football Ground in Melbourne, the Brisbane Cricket Ground, and the Melbourne International Flower and Garden Show.
Mr Reade said the trust was waiting until the public health service had finished its investigation before making any decisions.
Health officials, meanwhile, have been contacting organisations that had people at the test to advise of the outbreak and to set up interviews.
People who attended the event and are ill can contact the investigation team on 09 623 4600 during business hours.
