People who dined at a Christchurch restaurant earlier this month are being asked to contact the Canterbury District Health Board (CDHB) due to possible exposure to hepatitis A.
The CDHB says people who were at Madam Woo on St Asaph Street, on January 15 or 17, are at risk.
Urgent vaccinations are being offered to diners who have no previous immunity to Hepatitis A.
CDHB medical officer of health Dr Ramon Pink said there's a limited window to provide the vaccinations to get the best protection.
Dr Pink said people who dined on January 15 have until Thursday to get vaccinated, while those who dined on January 17 have until Friday.
He thanked Madam Woo staff for their cooperation.
"The team has been extremely good to work with," Dr Pink said.
"It's important to stress that there is no ongoing risk of infection to anyone who dines at Madam Woo now."
The restaurant says it is working closely with the community and public health and the situation is an isolated incident.
"An employee contracted hepatitis A while on an international holiday," a spokesperson told Newshub.
"[The] DHB has reviewed Madam Woo policies and practices, and there is no on-going risk to any diners. We take health and safety extremely seriously and receive the highest ratings in the industry on all annual food hygiene inspections."
The restaurant has now updated its policies so anyone who travels to high-risk countries must show proof of their immunisation against infectious diseases before returning to work.
People who were at the restaurant between those dates are urged to call 03 364 1777. For more information about Hepatitis A click here.