All schools in Christchurch, Selwyn district and Waimakariri are to be closed until at least Wednesday, following the earthquake.
The measure, which covers all institutions, both public and private, from pre-school to secondary schools, is under the Civil Defence Act.
Civil Defence says the decision is supported by health authorities and has been made in consultation with the Ministry of Education.
The Secretary for Education, Karen Sewell, says closing the schools will allow more time to ensure the safety and assessment of school property.
In other affected areas, school boards of trustees and early childhood providers will decide themselves if they need to close.
The Ministry has established an emergency call centre - 0800 225580 - to give principals and school boards ongoing advice.
Canterbury University remains closed and staff and students have been told to stay away until at least next Monday.
A preliminary assessment has found no serious structural damage to any of the university's 80 buildings, vice-chancellor of Rod Carr says, and it will be decided on Wednesday whether the university will be closed for longer.
Dr Carr says there have been chemical spills in laboratories, and about half a million books have fallen off library shelves.
Tai Poutini Polytechnic's Music and Audio Institute in Christchurch has brought forward its holidays and will be closed for the next two weeks.