The intersection of Hakeke and Holyoake streets in Whanganui East was cordoned off by police after a vehicle hit a pedestrian about 9.20am on Sunday.
A police spokeswoman said the pedestrian had suffered serious injuries.
"The Serious Crash Unit was dispatched to the scene at 9.40am," she said.
"The area where the crash happened will be blocked off while they [SCU] are there examining it."
A St John spokeswoman said one patient in a serious condition had been transported to Whanganui Hospital by ambulance.