The fire comes amid industrial action for all New Zealand firefighters covered by the union.
All career fire stations, training centres and 111 fire communications centres have stopped work for one hour from 11am to midday on August 19.
The New Zealand Professional Firefighters Union (NZPFU) has previously said there is "a fire crisis", with FENZ failing to employ sufficient career firefighters and 111 emergency call centre dispatchers to meet minimum staffing.
This has resulted, the NZPFU said, in the closure of some career stations, fire trucks have been taken offline and firefighters are riding in unsafe short-crews to keep the fire trucks responding.
