The Whanganui River is likely to breach at the Kowhai Park, resulting in flooding in some areas.
Kym Fell from the Whanganui District Council said evacuations will take place in low-lying areas of Anzac Parade and Putiki, starting from 12.30pm today
"We are working on evacuating households two houses deep from Anzac Parade and all of Putiki from SH4 toward the Whanganui River. The evacuations will be co-ordinated by police with support from the Defence Force and Civil Defence staff," Mr Fell said.
"We aim to have people evacuated by 5pm this evening. We ask that people are prepared with emergency kits and essential items including medication."
Residents in these areas will be asked to make their way to the Civil Defence centres at either Whanganui Girls College, Jones Street, Whanganui East or St Paul's Church in Guyton Street.