Tas school extension plan working: govt

More students are staying at school for years 11 and 12 under a plan to extend Tasmania's high schools, the state government says.

The island has recorded some of Australia's worst secondary education retention rates under the traditional system where young people go to college to complete their secondary education.

Figures released on Tuesday showed that across 12 schools that offered the extension, 275 students enrolled for the additional years which is a 57 per cent increase from 2014 according to census figures, Education Minister Jeremy Rockliff told state parliament.

"A further 18 schools will extend in 2017," the minister said.