"The main factors are the population rising, the ageing population that adds more cost, and increasing cost of things that need to be purchased."
At a national level health was found to be underfunded by $215 million, despite the recent increase.
Health Minister Jonathan Coleman responded by dismissing the report and emphasising this year's increased health funding.
"It's an election year and these are Government critics. Health has remained the Government's number one funding priority."
A $26 million shortfall was reported in funding for elective services at a national level, $17 million for disability support services and $7 million for maternity services.
National mental health services were about $5 million short, the economists said.
The CTU and ASMS produced another joint report earlier this year analysing mental health budgets, which found the recent $224 million boost was not as good as it appeared.
The money would be distributed over four years, and some of the money was already part of basic DHB budgets, according to the unions.
The actual funding increase was just 1.2 per cent, Rosenberg said.
"When we took the figures apart to understand what the Government was going to pay for and where the extra money was, we found that it was all smoke and mirrors."
The unions found funding for 16 of the country's 18 health boards was less than what was needed.
Counties-Manukau DHB was shortchanged by $21 million and Canterbury by $17 million, the report said.
The economists did not take into account factors such as poorer health and deprivation.
Northland had the lowest average income of any New Zealand region last year, according to Statistics New Zealand figures.
The Northland DHB declined to comment.
