Health and Disability Commissioner Ron Paterson is calling for the establishment of a national quality agency.
Details issued on Monday covered the period to June show that 308 public hospital patients were involved in serious errors last year, and that 92 later died - although not necessarily as a result of the mistakes.
The so-called Serious and Sentinel Events report from district health boards was released by the government-appointed quality improvement committee.
Clinical management issues involving diagnosis or delayed or inadequate treatment were behind almost 40% of all incidents. Falls came next at 27%, followed by suicide at 12%.
Mr Paterson says the number of the errors reported by district health boards will continue to rise as they expand efforts to identify and address problems.
"It's still a bit mickey mouse, frankly, to have a number of separate initiatives - this one being led by this DHB and this one being led by another.
"Surely in a country with four million people we can coordinate our efforts nationally, so that we can take things that work that we know have worked."
Mr Paterson says private hospitals and medical centres should also be covered in future releases about Serious and Sentinel Events.
The commissioner also says it is time to set up a national quality agency to drive improvements in a co-ordinated way.
The Government is considering that now, and is expected to make its decision known by Christmas.