Complaints about health and disability services have risen dramatically, Health and Disability Commissioner Anthony Hill says.
Mr Hill made the comment at Parliament's health select committee on Wednesday, telling MPs the workload of his office had risen substantially in the past three years.
He said last year 1551 complaints were received -- 12 percent more than the year before -- and the office would resolve 1850 complaints this year.
"The increase seems to be coming across the board, so we note the pattern of rising complaint levels consistently, sustainably and generally across the health and disability sectors.
"It is notable that mental health is increasing significantly."
Mr Hill said several factors could be involved, and he had no evidence a deterioration in the quality of care had sparked the increase in complaints.
