Paying to earthquake-strengthen fire stations and replacing older fire engines will lead to an overspend, the Fire Service says.
Commanders want the government to allow them to collect higher levies, as it struggles with its annual revenue of $372 million.
The service is funded mainly through levies on insurance, and is asking ministers to approve a short-term temporary increase in the rate.
Fire Service Commission chairman Wyatt Creech said in its annual report it was responding to more non-fire emergency call-outs, such as medical jobs and road crashes.
It was also making its fire stations more earthquake resistant, replacing other stations and renewing its fleet of fire engines.
Without extra funding, it would need new borrowing powers to continue operating and to pay for bigger projects, such as seismic strengthening, Mr Creech said in the report.
"Financial sustainability remains a major concern of the Commission with deficits now being forecast in out-years. In addition to ongoing operational cost pressures there are significant demands for capital to pay for the Christchurch rebuild and the national seismic strengthening programme."
However, the financial pressures had not stopped chief executive and national commander Paul Baxter getting a pay rise; the report showed his salary went from a maximum of $360,000 to up to $410,000.