A second healthcare worker who has recently returned from West Africa is being tested for the Ebola virus.
Health Minister Jonathan Coleman said a Nelson nurse was being cared for in special isolation facilities at Wellington Hospital. There are no other patients in the unit.
The hospital said that staff caring for the Nelson nurse had all volunteered for the work.
Clinical director of medicine at Wellington Hospital Grant Pidgeon said the hospital was well-prepared whatever the outcome is.
"The staffing that we use in this particular protocol, they are all volunteers who have put up their hands to assist in this specific circumstance, and they have then received the training that they require for this."
Dr Coleman said she was part of a seven-strong team that was the Government's contribution to an Australian Government-run centre in Sierra Leone in West Africa.
He said the woman, who has not been named, left Sierra Leone on 15 April and returned home last Saturday.
He said she started feeling mildly unwell yesterday morning, but he had been advised she was unlikely to have Ebola and stressed that the public did not have anything to worry about.
Test results being analysed in Melbourne were expected to rule out Ebola in the next day or two.
He said the only person to have been in contact with the patient was her partner, who was also being monitored.
The ministry's chief medical officer Don Mackie said her symptoms were minor.
"We're not going into any particular detail on the symptoms, but they're quite minor, and the technical advisory group and the clinicians involved have the view that it's not a particularly urgent situation, so we decided we'd work through and transferred the individual to the hospital today."
In March a Gore-based health worker was cleared of Ebola after returning from Sierra Leone.