The Gauteng Department of Education said it would shut down 200 under-performing high schools next week.
Spokesman Panyaza Lesufi yesterday said the department would give the schools until the end of the month to present their "turn-around" strategies to the department.
"We cannot continue to fund schools that do not perform to expected levels. We will go through their improvement plans and, if they cannot convince us that they will succeed, those schools will be closed," he said.
He said before a school was closed, the affected community would be informed and allowed to air its views.
"We will leave it to the community to decide how best the buildings can be utilised if a school is closed," he said.
Lesufi said the Vaal and central Johannesburg had the highest number of schools eyed for closure.
"Alex Commercial College, which is separated by a fence from Alex High, has consistently produced below par results while its neighbour is doing well," said Lesufi.
He said pupils whose schools are closed would be placed at nearest schools with better plans to ensure success.
Spokesman for the South African Democratic Teachers Union, Thulas Nxesi, said the department was "shooting from the hip".
"Closing down schools is not a solution. The department has a programme to monitor the progress of individual schools, but district officials do not visit those schools during the year," he said.
Nxesi said it was unfair to measure the overall performance of a school based on its matric results.
"The department has to put in more support for other levels of the schooling system," he said.
In November Gauteng MEC for education, Angie Motshekga, made a passionate plea to parents to get involved in their children's education.
Motshekga said the department's research showed some "parents were raising spoilt brats and arrogant prima donnas that our schools cannot handle".
She said investigations into problems faced by schools showed that dysfunctional parenting was a contributing factor.
Motshekga said many parents hoped schools would "fix" their wayward children.
"We cannot emphasise enough that every child belongs to a community and becomes the responsibility of everyone.
"Parents must take responsibility for their children's behaviour as well," she said.