The Whanganui District Health Board remains underfunded by more than $800,000 a year, unions say.
The new report from the Council of Trade Unions (CTU) and the Association of Salaried Medical Specialists (ASMS) said nearly all health boards required more funding.
Another $215 million would be needed nationally over the next year to keep up with population changes, inflation and wage increases, the report said.
Whanganui DHB chief executive Julie Patterson said the board was pleased with the recent increase in Government funding for health services.
"Whilst Whanganui DHB would always welcome funding increases we recognise the fiscal constraints within which Government must operate.
"We also acknowledge that health continues to receive greater funding increases than most of the other public services.
"As a DHB our role is to ensure that the funding we receive is utilised to provide the best value possible to the community we serve."
The report found some larger DHBs, such as Counties-Manukau in Auckland, were underfunded for the next year by as much as $20m.
The Whanganui DHB's total budget for next year was more than $200m, meaning the apparent shortfall accounted for less than 0.5 per cent of the annual budget.
The necessary funding was calculated in the basis of population changes, as well as inflation and wage increases.
"They don't fully fund for rising costs," CTU economist Bill Rosenberg said.
"They have to fund fully for the increasing population and the ageing population."
There has been no significant increase in Whanganui's population - it is the same as it was in 2011, according to Statistics New Zealand estimates.
Nationally, elective services were found to have a $26m shortfall and disability services a $17m shortfall.
Maternity services, child health, mental health and emergency services across the country were also significantly underfunded, according to the CTU and ASMS.
"New Zealand ranks poorly against other comparable countries on access measures such as barriers to primary care, and waiting times for elective surgery," Dr Rosenberg said.
Figures for primary health care funding were not available at a national level but the latest National Health Survey results suggested problems with primary care, according to the report.
Health Minister Jonathan Coleman said the Government had increased health funding.
"Claims by Government critics that health funding has been cut are incorrect.
"Under this Government health expenditure share of GDP has averaged 6.5 per cent - that's up from the previous Government's level of under 6 per cent."
The unions were particularly critical of mental health funding, calculating a shortfall of $1.1m despite the funding increase announced earlier this year.
The $224m boost promised by the Health Minister was to be spent over four years and included $100m from existing DHB budgets, the report said.
"Nowhere is unmet health need more apparent than for those requiring mental health care, as has been well documented in various reports," Dr Rosenberg said.
The mental health services would receive just 1.2 per cent more funding next year, Dr Rosenberg said, despite requiring more than 7 per cent to maintain services.