The Education Union has threatened a mass pre-election protest and a possible statewide teacher strike over the secondary college changes.

A third stop work meeting will be held in Hobart today.

Teachers at two similar meetings in the north last week voted against the Tasmania Tomorrow system.

The Premier David Bartlett is standing by the reforms and has repeated his call for teachers to target him at the ballot box and not make students suffer.

Greg Brown from the union says he's not surprised by the Premier's stand.

"He foolishly has given himself absolutely nowhere to go because in Parliament on several occasions he's told the parliamentarians there that he is determined to stake his political career on this," he said.