It will be the biggest school fire seen for some time, and firefighters will be itching to light the match.
The unwanted buildings at the former Taihape College, on the outskirts of the central North Island town, will be torched over the next three days to provide about 100 firefighters with their biggest live training exercise.
Exercises will be carried out in individual rooms before the entire building is set alight in a final large-scale exercise.
The Fire Service usually only has small rural houses or commercial buildings for live training, says Whanganui area manager Bernie Rush.
"The scale of this exercise makes it unique for our crews and will present some challenging scenarios for them."
The college was closed in 2009 replaced by Taihape Area School, and the Ministry of Education declared the buildings surplus in 2012. The local volunteer brigade has identified the old college buildings as a major fire hazard.
According to the Wanganui Chronicle last year the community did win the battle to keep the college's gymnasium and hall.