One in five children in low decile schools is heading to school hungry, KidsCan says.
The children's charity said it was now feeding 20 percent of the students at the 742 schools it supported.
On average 30,000 children each week are getting food from the charity.
"For many children they are accessing our food programme three to four times a week," its chief executive Julie Chapman said, "So there is a significant need for food."
"We're not seeing a let-up in the need for food and in fact we're having an increase in the need for food. Just last week I had a teacher email me to tell me that they actually had children fainting because of hunger and that they needed that food support."
While she said government initiatives like its Families Package and measuring poverty were likely to have some impact long term there was a lot that needed to change.
"Housing is on everyone's mind, it's a huge thing particularly for the families we're working with. They're paying 60 to 70 percent sometimes of their income in rent and that leaves very little for those other basics including food, clothing.
"Until we see some real progress in that area we're not going to see the dial on child poverty shifting significantly. Certainly extra money is helpful but the reports that I hear from schools and families is that any extra money that's been given over the past year has been sucked up into rents and the cost of living so children aren't necessarily better off."
Ms Chapman said many would be starting of the 2019 school year on the back foot.
"If we just ignore the level of depravation that they're suffering we're putting our own futures at risk, we're putting their futures at risk.
"We really need individuals, business to get involved and get behind organisations like ours and ask the question 'what can we do to help make sure that children who are perhaps less fortunate than others still have an opportunity to take advantage of their education this year?'"
The Child Poverty Action group wants benefits raised by 20 to 30 percent to ensure children are not sent to school hungry.
Its communications advisor, Jenny Cartwright, said the responsibility should not fall on charities.
"Giving people an option where they now can send their children to school and know that they're actually going to get a lunch when otherwise they might not be able to which I think is bound to happen when somebody steps up to meet that need.
"The unfortunate thing is that we're becoming reliant on charity."
Ms Cartwright said her organisation also wants the Working for Families tax credit to be extended to people on the benefit.
'I think it's terribly sad'
Auckland Primary Principals' Association president Helen Varney said the figures backed up the experience of the city' principals.
"I think it's terribly sad. I think there's something wrong with our society if that number is that high. It's not acceptable at all but what we're finding is that schools are having to create a range of initiatives so they meet the need of their community."
She said particularly for those in Auckland the cost necessities like housing, food and transport made poverty a very real concern.
"What we're finding is that families are relying now on schools to support them in order to ensure their children are able to have the stationery, the clothing, the food that they need to be able to learn at school."
She said schools had become the social hub for communities, providing what they could.
"We know that there are going to be a certain number [needing support] at every school no matter what school you go to, what area, what decile, but obviously with this high ratio at some schools this is going to be a major part of their set up and organisation.
"What surprises me now is how many are being supported and that's a sad indictment on our society today."
Ms Varney said providing meals for students each day meant that people were working on that rather than the providing education.
"We all know a child must be well fed, they must sleep well and eat well in order to be able to learn. So if they come to school hungry our first priority is to feed them."
She said as well as working with organisations like KidsCan and Eat My Lunch, low decile schools were partnering up with high decile schools for support.
"There's a wide range of agencies that support schools to be able to support students in need but the question I ask is: 'Is this the job of a school?'
"Is this what schools should be doing or should this be something our government should be looking at more closely and providing better services to the families in order to ensure children are coming to school everyday ready to learn?"