The Ministry of Health would not say if the person was vaccinated against Covid-19 or not.
According to the locations of interest details, the person appears to have visited the Kai Iwi public toilet between midday on Tuesday November 30 and 6pm on Thursday December 2.
They then visited the Polson St Foodmarket between 1:15pm and 1:45pm last Friday.
People who were at the above locations within the times specified need to self-monitor for Covid-19 symptoms for 10 days after exposure.
"If symptoms develop, get a test and stay home until you get a negative test result," the ministry said.
The only place to get tested for Covid-19 in Whanganui is at the community-based assessment centre in the carpark at Whanganui Hospital.
Common symptoms of Covid-19 may include one or more of the following: a new or worsening cough, sneezing and runny nose, fever, temporary loss of smell, altered sense of taste, sore throat and a shortness of breath.
The ministry revealed the person, likely to have links to previous cases of Covid-19 outside of Whanganui, showed symptoms of the virus on Thursday and was tested on Friday.
The positive result then came in on Saturday.
The ministry said more locations of interest can be expected after investigations carried out on Sunday revealed the first two places.
There have been queues of cars seen at the testing station at Whanganui Hospital on Sunday morning.
A Whanganui DHB spokeswoman said the Covid-19 testing centre at Whanganui Hospital had been busy during the weekend.
"We don't have the exact figure at this stage but I can say that the numbers have been steady," she said.
She said there also appeared to be a "huge increase" in vaccination numbers as well but those figures would not be available until Monday morning.
As of Saturday night the Whanganui DHB area had 81% of its eligible population fully vaccinated.
Including those who had one dose pushed that figure to 89%.
Te Oranganui Iwi Health Authority chief executive Wheturangi Walsh-Tapiata said the positive case in Whanganui served as a strong reminder to follow public health guidelines.
She said she hoped to see the same increase in testing and vaccination numbers that happened in other regions where a positive case had been discovered.
"We have been very lucky so far so let's keep being lucky by following the advice on getting vaccinated and keeping up the good hygiene practices of hand washing and using sanitisers."
Since the beginning of the pandemic, the Whanganui DHB area, which also includes most of the Ruapehu and Rangitīkei districts, has had just nine cases of the virus - all in March and April last year.
Currently, the Whanganui, Ruapehu and Rangitīkei districts are at the red level of the traffic light system.
Vaccination clinics around Whanganui
Monday, 6 December 2021 Te Rito 62 Victoria Ave 6am - 4pm Walk in
Monday, 6 December 2021 Central City Pharmacy121 Victoria Avenue 9:30 - 12:30pm
Booked
Monday, 6 December 2021 Pasifika Church Puriri Street, Tawhero 10am - 12pm