Following the review of the 20-year-old Education Act, the state government intends to legislate to change the compulsory school starting and leaving ages of Tasmanian students.

Under proposed changes, the minimum age for pupils starting prep from 2020 and beyond will be four years and six months - six months earlier than they do now.

The leaving requirement for students who started high school in 2016 will be raised to the completion of year 12, a certificate III, or when a student turns 18 years old, whichever occurs first.

Changes will allow a child who is three years and six months by the start of the year to be enrolled in kindergarten in 2020.

The announcement came just hours after Education Minister Jeremy Rockliff said the government had found resources to employ another 213 teachers in the education sector this year.

Mr Rockliff said the new teachers announcement was a result of targeted investment.

"As a result of some difficult decisions we took to get the budget back on track, we are now reinvesting the dividends in the core services of government, including education," he said.

It was the same Hodgman government that cut more than 260 jobs from the education sector in 2014.

NAPLAN results were also released on Wednesday and showed Tasmania only met the national benchmark in three out of 20 categories that were assessed.

Details of other proposed Education Act changes will be released next week.