Salaries for staff at Northland's four local bodies have increased by $5.6 million in the past 12 months, with the Far North's bill rising by almost $2.5m.
Far North District Council paid staff an extra $2.4m last year and added an extra 52 full-time equivalent employees, its annual report shows.
But the acting chief executive Colin Dale said the costs are an investment and a part of rebuilding the council.
The 2015/16 financial year report showed salaries and wages for employees rose 13.8 per cent from $18.05m to $20.54m.
The council added 47 full-time positions, and five full-time equivalent, part-time employees to take the total head count to 330.
The total costs of staff salaries has grown 35.7 per cent, or $5.4m, since the 2012/13 financial year, up from $15.14m.
Mr Dale said the past few years have been a rebuilding process. Many areas were understaffed or not performing well including infrastructure and asset management, building services and Maori engagement.
He said the council has also brought previously contracted roles back in-house.
"Investment in our human resources was, and remains, a vital part of our strategy to rebuild an organisation that had been stripped of vital specialist services and that had left staff under enormous pressure to meet demands," Mr Dale said.
He admitted costs were rising significantly, but said the council still spent proportionally less on staff than the national average.
"The increase in staff ... has set the organisation in the right direction. It is all a significant cost, but I call it an investment, not just a cost."
Salaries of senior management staff grew 6 per cent. The average pay of the five staff grew from $203,200 to $215,400.
An extra four employees in the 2015/16 year earned more than $140,000, from seven staff to 11.
Nationwide annual wage inflation was 1.7 per cent in the public sector, and 1.6 per cent overall, according to Statistics New Zealand. This was the first time public sector wage inflation outgrew the private sector since 2010.
Northland Regional Council's total wage bill grew 5.9 per cent, rising from $11.4m to $12.07m.
It employed 15 extra full-time staff, and an extra five staff were paid more than $100,000 from the year before, taking the total to 14.
Whangarei District Council's wage bill rose $1.05m, or 4.85 per cent, to a total of $22.6m.
Chief executive Rob Forlong said the staff increases were largely to cope with the increase in construction sector activity.
"The good news is that the increase in personnel costs was more than offset by an increase in cost recovery fees ... We definitely feel this expenditure benefits our community."
Kaipara District Council's salaries and wage bill rose $810,000, or 13.4 per cent, in 2015/16, after it added 14 full-time roles.
Kaipara District Council's administration manager said Linda Osborne said the positions were in roading, environmental health, regulatory, waters and senior management. An extra four employees earned more than $120,000 in the year - from five employees to a total of nine.
A former director from the Office of the Auditor-General is highly critical of council staffing costs. Larry Mitchell said, in general, councils around the country were "bloated" with excess staff and salaries had increased markedly in the past decade.
"The control that's supposed to be exercised at that budgetary level is missing in action. The elected members, the councillors, the finance and audit committees are asleep at the wheel," Mr Mitchell said.