Whanganui motorists and pedestrians are being asked by police to avoid the area around the intersection of Campbell St and Ingestre St.
Emergency services were responding to reports of a possible gas leak at that location around 1.15pm on Tuesday.
A police spokesperson said traffic management was currently in place and some properties were being evacuated.
"An update will be provided once the situation is resolved."
One Campbell St resident said police had knocked on the door and asked people to evacuate their houses.
