Tauranga ratepayers shelled out almost $10m for consultants in the last year, while council staff numbers grew.
The $9.78m consultant bill, disclosed in the Tauranga City Council's 2016-17 annual report, was a 20 per cent jump from the previous year and close to double the $5.29m spent in 2014-15.
Meanwhile, council staff ranks swelled by 32 (5 per cent) to 588 full-time equivalents, growing staff salary and wage costs 11 per cent to $44m.
The number of staff in the top salary bracket - $200,000-plus a year - doubled from six to 13. The next salary bracket ($160,000 to $199,000) emptied from six people to one.
Tauranga mayor Greg Brownless said the council would prefer to keep consulting costs down.
"It is concerning to me to have spikes in either staff or consultants."
He said using consultants could be beneficial as a temporary measure for special projects - of which the council had many - saving the council the expenses that go along with employing people.
A fifth of this year's consultant spending, or $2m, went towards hiring outside help to deal with an unexpected boom in building and resource consent applications.
The use of consultants in the council's building services department has been controversial this year.
In June an independent review of the department found two contractors hired to help process consents were not accredited building consent authorities. The council stood by the work of those consultants.
The BDO review also found that in March alone half of consent processing was outsourced.
According to the annual report, that month the department also hit a two-year record for the most building consents received in one month, with 310.
In total it processed 3273 building consents, up 6 per cent on the year before.
The council's consulting bill also included money for outsourced legal work and modelling for wastewater and stormwater planning, as well as various other projects.
The council ended the financial year with net $301m debt.
It was more than last year but less than budgeted, councillors heard during a brief meeting to receive the report on Monday.
The 313-page report outlined the council's activities and performance for the year.
Debt was up $4m on the previous year but considerably less than the $391m the council had budgeted for.
This was put down to two factors: delays in delivering some big-ticket infrastructure projects, resulting in a budget surplus, and millions more in fees paid by developers than the council was expecting.
The council budgeted for $20m revenue from development contributions but made $36m.