NSW Health and the NSW Food Authority are continuing to investigate a significant foodborne outbreak following a conference on the Central Coast last week.

At least 69 people from across NSW, the Northern Territory and Queensland are known to have become unwell with symptoms of food poisoning, of which 27 people have confirmed Salmonella infections to date.

Dr Jeremy McAnulty, NSW Health Executive Director of Public Health, said public health officials from across NSW have been working to speak to all those who have become unwell after attending or working at the conference.

"Close to 230 people attended or worked at the two-day conference, and so far at least 31 of them are known to have attended Emergency Departments," Dr McAnulty said.

"NSW Health is working closely with the NSW Food Authority to investigate the cause of the outbreak.

"Our public health experts continue to contact people associated with the event, including attendees from the Aboriginal Languages Trust and we thank all of those who have assisted us so far.

"We ask anyone who feels unwell or has concerns about their health after they have returned home to seek medical care, and to get in touch with your local Public Health Unit, or the conference organisers," he said.

Acting Director Food Safety and CEO of the NSW Food Authority Anthony Zammit said the Authority has taken action to ensure there is no ongoing risk to health from the venue.

"NSW authorities are investigating the cause of suspected food-borne illness cases linked to a function at the Crown Plaza Terrigal Pacific hotel, and as a precaution, the hotel voluntarily closed the kitchen," he said.

"The closure was also formalised through a Prohibition Order issued under the Food Act 2003 preventing the use of one kitchen. Our compliance officers have visited the venue to collect samples and the investigation is ongoing."

Salmonella is usually spread to humans by eating under-cooked food made from infected animals (for example undercooked meat, poultry and foods from animals such as eggs). It can also be spread from person to person, but this this type of transmission usually occurs over several weeks instead of a couple of days.

Most people recover by having lots of rest and drinking plenty of fluids such as water or oral hydration drinks (from your pharmacist). However, some people can experience severe infection and may require admission to hospital for rehydration.

Some severe infections can lead to sepsis, bacteraemia and occasionally cause disseminated disease or secondary complications, such as endovascular infections (inflammation of blood vessels, endocarditis) or bone and joint infections, particularly in those who are immunocompromised.

NSW Health strongly encourages anyone who ate food at the venue who remains unwell to seek medical care including a full medical review and examination.