There were 70 schools under the control of statutory managers or commissioners at the start of this month.
Secondary Principals' Association president Tom Parsons said the message that schools would be taken over because of student achievement data would be a "frightening scenario" for many. However, he said if such information was used carefully - to help collaboration between high and low performing schools, for example - the Government's focus on data could benefit schools and students.
Allan Vester, chairman of the NZ Secondary Principals Council and head of Edgewater College in Pakuranga, said care would need to be taken to properly understand what the data was showing and measuring.
" ... the minister needs to make sure that it does not become a process of blaming schools for situations beyond their control."
National standards describe what students should be able to do in reading, writing and mathematics as they progress through levels 1 to 8, the primary and intermediate years.
Problems with the data were underlined in a ministry report this month which found teacher judgments on children's relation to the standards lacked dependability.
But Ms Parata said those issues would be ironed out as the standards were bedded in. By themselves they would not be used to justify any action, but would form a case together with Education Review Office reports and other information.
Schools in the gun
* Government could step in and take over schools if students' marks aren't good enough, Education Minister Hekia Parata says.
* Currently interventions made because of major staffing, safety or financial issues.
* Change in approach signalled by Ms Parata comes after a focus on student achievement data, including controversial national standards.