Public Health England said on Friday that the patient involved had recently returned from Italy.
It said it was contacting people who had been in contact with him or her. No details have been released of where exactly in Lincolnshire the case has been identified.
Dr Fu-Meng Khaw, Centre Director, Public Health England East Midlands, said: “Public Health England is contacting people who had close contact with one of the latest confirmed cases of COVID-19. The case is a resident of Lincolnshire and recently returned from Italy.
“Close contacts will be given health advice about symptoms and emergency contact details to use if they become unwell in the 14 days after contact with the confirmed case. This tried and tested method will ensure we are able to minimise any risk to them and the wider public.”
Lincolnshire County Council says it is doing everything it can to help stop the virus spreading.
Derek Ward, Director of Public Health for the council, said: “I’d like to reassure people that the risk to the general public remains low and the local authority is working with health colleagues to do everything we can to stop the virus spreading and ensure the people of Lincolnshire are protected.
“Good hygiene is the best prevention and there are some simple steps you can take to protect you and your family by washing your hands regularly and thoroughly and if you cough, cover your mouth and nose with a tissue.
“If you have recently been to one of the affected areas and are feeling unwell, you should phone the NHS 111 helpline for further advice straight away – please don’t go to your doctor or a hospital. There’s lots of advice on how people can protect themselves online at www.nhs.uk/coronavirus.”