The Coalition party describes the laws as "a level of state control and bureaucracy which is not required".
The Associate Education Minister was at Freyberg High School when a student spat at his feet.
It happened as the Associate Education Minister was leaving the school.
Seymour was at Freyberg High School on Thursday to talk to some of the school leaders about truancy.
Finance Minister Nicola Willis has promised tax cuts in the May Budget.
National has promised the legislation won't make it through Parliament.
If passed, it would allow retailers to keep their doors open as normal through Easter.
Sir Collin Tukuitonga said he was "appalled" at the Government's decision to repeal smoke-free legislation.
The new coalition Government plans to repeal a ban on exploring for new oil and gas reserves off the coast of New Zealand.