Tens of thousands of children are again taking to the streets over climate change action - and this time, they want Kiwi workers to march with them.

Nearly 100 businesses and universities around the country today join pupils for the third - and expectedly biggest - School Strike 4 Climate protest.

It caps off a week in which the movement's 16-year-old figurehead Greta Thunberg dressed down a summit of world leaders, and a major UN report warned time was fast running out to solve the climate crisis.

More than 40 events around New Zealand are scheduled today, from large demonstrations in main centres to rallies in places as remote as Great Barrier Island.

"We are definitely expecting it will be the biggest turnout yet," said the strike's national co-ordinator, Paekakariki teen Sophie Handford.

Last Friday, millions of young people packed out parks in world cities like Sydney, Berlin and New York, as part of the global push.

Handford said New Zealand's events had been scheduled a week later as many pupils were sitting school exams.

"But there happens to be a global strike on September 27 as well, involving 170 countries and more than 6300 events – so we are looking at something the same size as last week."

Today's event was organised in solidarity with Wellington protester Ollie Langridge's weekly vigil on the lawns of Parliament, calling for the Government to declare a climate change emergency.

Handford was heartened that workers from 90 businesses – ranging from bookshops and bakeries to consultancies and architecture firms – would be downing tools to take part.

"We've deliberately scheduled our events around lunchtime, so adults can join us by taking a longer break. We'd like the focus of this event to be not just on students."

Unlike the country's first rally on March 15 – quickly overshadowed by that day's terror attack in Christchurch – there had been seemingly little push-back from schools this time, she said.

"It's helped that universities have jumped onboard, and that we've had some good conversations with the main teachers unions," she said.

"But also, we've seen students are becoming a lot more willing to take action, regardless of what their school is saying, because there is so much at stake, and that this is the most important issue for so many young people in New Zealand."

Many Government and council leaders have voiced their support for the drive – but not all of them.

Acting Prime Minister Winston Peters said pupils should be staying in school, adding they could learn all they needed to know about climate change by "seeing what the Government is doing".

The Ministry of Education has meanwhile shared guidelines with schools around attendance and legal responsibilities.

Further marches – or other forms of action - weren't being ruled out, Handford said.

"We are committed to doing this until we see our demands met."

She said people could also help their cause by signing an open letter urging the Government to declare a climate emergency, cease all extraction and exploration of fossil fuels and pass a Zero Carbon Act that strived for net zero carbon emissions by 2040.

Earlier in the week, 16-year-old Thunberg scolded leaders attending a UN climate summit in New York, telling them: "We are at the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth."

At that conference, Prime Minister Jacinda Ardern announced a new climate trade agreement that sought to remove tariffs on environmental goods, set concrete commitments to eliminate fossil fuel subsidies, and develop voluntary guidelines for eco-labelling.

On Wednesday, the UN released its latest special report, warning that rising, warming, acidifying oceans and melting ice could be affecting more than a billion people by as soon as 2050.

Whether sea levels rose by between 30cm and 60cm - or by up to a vastly more damaging 110cm - depended on emissions being slashed enough in the next two decades to keep warming below 2C above pre-industrial levels.

'Nothing will stop me from doing what I feel is right'

Hamilton 17-year-old Timi Barabas explains why she's marching in today's School Strike 4 Climate.

My dream is to make a difference in the world and change what can be changed.

My biggest goal is to help people and bring peace and equality into this world.

I am marching because enough is enough. I am fed up with adults telling us young people that we can't achieve great things and make a difference.

I want to prove to people that it isn't about how educated you are, but about the goal that you have.

Our goal is unifying together for the common purpose of protecting our planet. Nothing will stop me from doing what I feel is right.

And I don't think it is right to sit at home and write negative comments about people who work so hard for change – who actually get up and do something.

I am originally from Hungary, which just experienced one of the hottest summers in its history.

The winters there are now very cold and the summers are very hot. This is not how it used to be. Since I moved to New Zealand, things have also changed.

Climate change does exist. And there is so much work to do.

I want to see businesses and world leaders, all around the world, start making the protection of our planet and future a priority.

I want to see them listening to us and taking us seriously.

• Timi Barabas is a Year 13 Rototuna High School pupil and a BLAKE Inspire 2019 delegate.

What's happening where

WHANGAREI:

Corner Bank and Cameron St, 8am-noon

AUCKLAND: Aotea Square, CBD, Noon-3pm.

HAMILTON: Civic Square, 1pm-4pm

TAURANGA: The Strand, Noon-3pm

ROTORUA: Village Green, 2pm-4pm

WHAKATANE: Mataatua Reserve, Noon-4pm

GISBORNE: Childers Rd Reserve, 12pm-3pm

NAPIER: Soundshell, 10.30am-2.30pm

TAUPO: Colonel Roberts Reserve, 12.30-3pm

NEW PLYMOUTH: Huatoki Plaza, 11am-3pm

WHANGANUI: Majestic Square, 9am-1pm

PALMERSTON NORTH: Palmerston North City Council, Noon-3pm

LOWER HUTT: Dowse Square, 8.30am-9.30am

PORIRUA: Porirua Railway Station, 8.30am-2pm

WELLINGTON: Parliament, 11am-2pm

NELSON: Church Hill Pikimai, 12.30pm-3pm

BLENHEIM: Seymour Square, 12.30pm

CHRISTCHURCH: Cathedral Square, 1pm-3pm

TIMARU: Timaru District Council, 11am-12pm

DUNEDIN: Dunedin Dental School, Noon-3pm

INVERCARGILL: Feldwick Gates, 12pm-2pm

• For a list of all events, visit the Facebook page.