“It is a tragedy our kids spend less time at school than in mainland states,” Mr Rockliff said.

“This is an equity and social justice issue for me.

“Over the last 14 years in parliament, I have been  very committed to social justice issues, particularly around equity.

“This is about providing Tasmanian students with the same opportunities as in other states.

“Our education outcomes have to be improved upon.

“We cannot sit by and talk about the challenges in education and do nothing.”

The government is planning to lower the compulsory starting age for prep from five years to 4.5 years.

The starting age for non-compulsory kindergarten would drop from four years to 3.5 years.

The plan has attracted opposition from the childcare sector, Labor, some parents and others.

Issues raised by critics have included that children who are not ready  will be required to go to school,  they are better suited by childcare,  queries about resourcing, childcare businesses will suffer and some might close and school starting ages are significantly older in some countries which do well on education, particularly Finland.

Mr Rockliff said the government understood adequate resources would need to be provided to help schools cater for extra children, including staff and infrastructure.

He said the government  had committed to funding an initial estimate of an extra $15 million a year, and suggested the number would go higher if required.

“This whole change is about effectively extending our universal public education system,” Mr Rockliff said.

“It’s all about bringing us in line with other states in terms of lowering our starting age.

“All  the evidence points  to the fact the earlier we can engage kids in quality early learning, the better.”

He said 40 per cent were denied access to that (through childcare) because their families could not afford it.

“All we’re doing is bridging that gap and allowing the public education system to provide earlier access for kids in quality early learning environments,” he said.

”This is a very important change and a great opportunity,  but I don’t see it as radical when other states have access to quality early learning at four years, five months, for example.”

He said 20 per cent of children in the region were vulnerable in at least one learning-related area and it was up to 30 per cent in some areas.

”These are the children and families we need to engage in education … that are currently denied the same opportunities as kids that can access childcare.”

Mr Rockliff said children in the public system would continue to be treated in an age-appropriate way after the changes.

“I have enormous regard for our kinder teachers, our teachers’ aides and kindergarten can be accessed now at four,” he said.

“It is  play-based, it is inquiry-led and it will continue to be.

“The first year of formal schooling is grade 1.

“Kindergarten is not compulsory and prep is  a preparatory year, including play-based activities and to  prepare for grade 1.

“To suggest three and a half-year-olds  will be sitting up behind desks with pencils as some people are trying to paint is breathakingly ridiculous.”

Mr Rockliff said changes to the Education Act were announced in September 2014 and it would be a further three years from this year before they took effect.

He said that allowed plenty of time for planning, understanding the needs of schools, the impact on the childcare sector and working in partnership with childcare.

He acknowledged the childcare sector would be affected and said Treasury was preparing a regulatory impact statement.

“My view is we can work with childcare businesses  to ensure there is a smooth transition that does not adversely impact on their business and, where possible, find greater opportunities for childcare centres to  work in partnership with the education system,” he said.

“We’re all in this together and have a responsibility as a community to give all our kids the absolute best opportunity.

“If through policy change and additional investment we can inject some equity and social justice for those children who don’t have the opportunity to access quality early learning, we have to take responsibility as a community and do something about it.

“The reason why we are not rushing this change is we  want to engage with communities, the  schools sector and the childcare sector to ensure the smoothest transition possible.

“There will be an impact (on childcare), but I cannot hold back from providing future generations of children with a better opportunity because of a potential impact on business.

“We have to be open minded when it comes to improving education outcomes in Tasmania.

“We cannot expect to have different and better results … if we stay the same.”