The National Party says a report from the Business Roundtable pointing to a continued decline in the productivity of public hospitals contains nothing new and offers no solutions.
The report said the average cost of hospital services rose 18% between 2001 and 2006, but overall staff productivity fell by 8%.
Business Roundtable executive director Roger Kerr said this was despite large increases in health spending.
He said the report backs 2005 Treasury findings of a fall in hospital efficiency at that time.
Expenditure in the sector accounts for a fifth of Government spending.
National Party health spokeperson Tony Ryall said the report appears consistent with conclusions from the Treasury over the past few years.
Health Minister David Cunliffe said the fundamental weakness in the report is that it confuses efficiency with effectiveness.
Former Treasury Secretary Dr Graham Scott, who wrote the foreward to the report, said health funding has been increasing by about 8.5% a year.
Association of Salaried Medical Specialists executive director Dr Ian Powell said the report was weak and information has been manipulated to make an ideological point.