A worker at the Yakatori Takumi restaurant in North Adelaide has tested positive to hepatitis A, potentially exposing diners to the disease.

Health officials said they believed the worker picked up the infection while overseas.

Chief Medical Officer Paddy Phillips said the risk to customers was considered low, adding, "However, it is possible that patrons who ate at the restaurant between September 21 and October 4 may have been exposed to the hepatitis A virus. An alert has been issued to all GPs to be aware of the case and to arrange for appropriate testing for any patients presenting with possible hepatitis A infection."