The only exception is Ohakune, which has a complement of 26 - one more than its minimum. Rangitikei's six volunteer brigades in Bulls, Hunterville, Mangaweka, Taihape, Ratana and Marton are down a third, or 41 volunteers, on their minimum total of 125.
"When a brigade can't turn out an appliance, the job falls to another one further from the scene of the incident. Frequently that means a longer wait for those who've called for help.
"The stark fact remains that after 10 minutes it becomes much harder to save a property that is alight - or to rescue anyone trapped inside."
Mr Rush said the problem was not new, but had become more pronounced recently. He said the fire service was working on a range of measures to boost volunteer numbers, including easier induction, more flexible training arrangements, more support for employers of volunteers, and more use of some volunteers to do non-operational duties such as administration and maintenance, freeing up others for frontline work.
"There are genuinely great things about being a volunteer. The sense of contributing to and being part of the community is a much underrated aspect of the job. Also, volunteers receive training in a whole range of disciplines - training that is transferable to other workplaces, as well as, of course, helping to save lives and property."
People interested in volunteering as a frontline firefighter or brigade administrative assistant should contact their local brigade directly, on one of two support officers listed below.
For Ruapehu, brigade support officer Aaron, 027 4571 600.
For Rangitikei, brigade support officer Colin, 027 4428 433.