The event was initiated by Ardern and she apparently wanted it during a lunch hour to avoid disrupting studies and to hold it ahead of the climate change strike.
The strike on Friday is part of youth-led global action on climate change.
New Zealand organisers of the School Strike 4 Climate protest believe hundreds of students from across the country will take part.
The organisation has written an open to politicians, parents, business and teachers.
"For over 50 years we have known that climate breakdown poses an existential threat to life on Earth," it says.
"We have known that we cannot afford to keep burning fossil fuels, and depleting our oceans, rivers, forests and land. And yet we have continued to do just that.
"Soon we will inherit the consequences of this inaction, and we are scared.
Will we have a planet worth passing on to our children? Will we face global conflicts because of resource scarcity? What will we do if the ecosystems we depend on completely collapse? Where will all the people who lose their homes go? These are the questions looming over our generation."
The organisation wants New Zealand to reach carbon neutrality by 2050 or sooner, limit warming to 1.5C, pass an effective Zero Carbon Act, and ensure responses to climate changes are transparent and fast tracked.
Government policy is for New Zealand to be carbon neutral by 2050 and to Shaw is consulting on a Zero Carbon Bill.
He is setting up an independent Climate Change Commission to advise the Government and has funding for a $100 million green investment fund.
Aredern, aged 38, has described climate change as the "nuclear issue" of her generation.
