Many children will turn up to school without uniform or stationery, teachers say (file photo).

Three weeks. That's how long it will take for Taumarunui Primary School to have a full roll once the new school year starts.

Not because children are off on long summer holidays, but because parents don't have food to send in their lunch boxes and can't afford back-to-school supplies, teacher Sharon Shaw says.

When students do turn up for the new school year, it's in "dribs and drabs", often without uniforms or stationery.

The teachers are used to it; they'll buy supplies out of their own money, keep the stationery list as brief as possible and make sure they don't make a big deal out of it.

But there's no getting around the fact that it makes for a tough start to term: it's hard to get learning started when there are empty chairs, and hard for children to catch up when they've missed the first chunk of school.

Across the country, students will be absent at the beginning of term because they are sharing one uniform, a pair of shoes or a bus pass with their siblings, a new KidsCan survey shows.

"We had [four] boys attending on different days of the week and the excuse was illness," one teacher wrote.

"Turned out they only had one school shirt so they picked their favourite day of classes to come. Mum was too embarrassed to tell anyone."

Chris McKeen/Stuff Making sure children aren't hungry in the classroom makes all the difference to their learning, teachers say.

Teachers also said children felt embarrassed and anxious because they were missing equipment: "We've had children with sore stomachs, anxiety, crying etc because they do not have the right uniform, stationery, shoes or money to go on camps".

Taumarunui Primary School receives food, coats, shoes and toiletries from KidsCan. But before KidsCan was on the scene, Shaw was doing her own bit to make sure no child was starting the day hungry.

She set up a breakfast club 16 years ago. She said she couldn't believe the difference it made to "everything": children started learning better, their attention spans were longer, they stopped stealing lunches because they had the security of coming to school and getting fed.

RYAN ANDERSON/STUFF Students at Manurewa High School make toasties from KidsCan supplies for their classmates.

The 2019 Child Poverty Monitor showed 148,000 children were living in material hardship and tens of thousands were going without healthy food.

For Waikato principal Kevin Ikin, that reflects what he sees in his community. People don't realise the depth of poverty that exists all over New Zealand, he said.

When some children at his primary school went home at night it was to a tent or a car, or to a house they shared with multiple other families.

This wasn't just in families where the parents weren't working, he said – they might have two or three jobs.

It was a "real concern" when children stayed home because there wasn't enough food, but it happened regularly, he said.

He tried to build up a relationship with families so they felt able to ask for help: "It might sound real easy … but you've got to remember, people have pride, they have dignity."

MURRAY WILSON/STUFF KidsCan provided more than 424,500 hot meals in 2019.

The culture he was aiming for was transparent, open-minded and approachable, where kai was always available so kids didn't feel embarrassed coming forward and could tell their parents they could get food at school.

Ensuring dignity for the children and their whānau was crucial, he said.

"It's about giving them agency and ownership. They don't feel embarrassed or ashamed to ask, because you're not asking – we're actually offering."

Nelson Intermediate School principal Dianne Webb agreed building relationships was crucial, especially when it came to handing out sensitive items such as the tampons and pads provided by KidsCan.

ALDEN WILLIAMS/STUFF The family budget often doesn't stretch to sanitary items.

Some girls would skip school when they had their period because they could not afford sanitary products but the efforts of the KidsCan coordinator at the school meant now even the "most shy girls" felt comfortable coming forward, she said.

In 2019, KidsCan provided more than 28,200 boxes of sanitary products to schools. Every day, an average of 30,000 children were fed with deliveries of baked beans, bread, spreads, fruit, yoghurt, supergrain bars and scroggin.

This term, the charity is bringing 47 schools off its waiting list, supporting a total of 787 schools.

* People can donate at www.kidscan.org.nz