Scores of Afghan schoolgirls have been knocked unconscious or made ill following a suspected poison gas attack on their schools.

Authorities are blaming insurgents who oppose educating girls. Provincial police chief Abdul Razzaq Yaqubi said about 48 girls and several teachers had become ill suddenly and many collapsed after smelling poison gas at a school in the northern city of Kunduz on Saturday.

A Taliban spokesman denied the group was responsible, but said other anti-government groups could be to blame.

"We strongly condemn such an act that targeted innocent school girls by poisonous gas," Taliban spokesman Zabihullah Mujahid said.

The Taliban banned all education for girls when they ruled Afghanistan from 1996-2001, and schooling for females remains a controversial issue in much of Afghanistan.

In the south and east, where the Taliban control towns and villages, schools for girls remain shut, teachers have been threatened and some girls have been attacked with acid.