A group of health experts is urging the government to expand its free lunch scheme to more schools.

Health Coalition Aotearoa says more children than ever need the scheme because of the cost of living crisis, and in Auckland the floods has added to the pressure on some families.

Coalition co-chairperson Boyd Swinburn says Ka Ora Ka Ako the Ministry of Education's Healthy School Lunches Programme is restricted to schools that have the 25 per cent of students with the highest socio-economic need and it should be at least doubled to the next 25 per cent.

Professor Swinburn says he has been studying the effect of Ka Ora Ka Ako in schools in the Hawke's Bay and it has benefits for education and health and even for local employment and food security.

"There's a heck of a lot of positive spinoffs from this programme.

"For the kids themselves, I mean we're still in the middle of a childhood obesity epidemic for which there's been virtually no interventions apart from this so we desperately need action on childhood obesity, but there's a whole lot of other spinoffs as well for health including oral health and also mental health."

Swinburn says the research also found that a lot of children who would benefit from Ka Ora Ka Ako are missing out.

"In the mid-decile schools there are a heck of a lot of kids who are still facing food hardship, food insecurity at home and so I think it definitely needs to be spread to those schools, where they still have a very high percentage of kids who are facing food insecurity at home."

Nearly 1000 schools, with 250,000 students, are in the scheme this year.

University of Auckland research fellow Victoria Egli, who was also a Health Coalition food expert, says there's overwhelming support for Ka Ora Ka Ako in the schools that received it.

But she says more schools need it.

"At the moment only 25 per cent of children receive lunch at school and what it does is it misses a lot of children who are still living in food insecure households. So children can be food insecure outside of that 25 percent and we're missing those kids."

Dr Egli says ideally, the programme should be expanded to all schools.

"Expanding the Ka Ora Ka Ako programme to all kids in all schools will, most importantly, ensure that kids going to school in Aotearoa are fuelled on healthy, nutritious food."

Māori health organisation Hāpai te Hauora chief executive Selah Hart says it ran a brief online survey of families after Auckland's floods and found high demand for food.

"Food was the number one priority," she says.

"Food security or insecurity is so high right now. It was already high prior to the floods."

Hart says the government should expand its lunch scheme, and after three years of dealing with the pandemic there are plenty of organisations that could help it do that quickly.

"As a small Māori health provider across a wider network of Auckland Māori health providers we can mobilise kai packs with our eyes closed. I know providers right across Auckland, right here right now, that are delivering hundred and hundreds of kai packs out to families. So there are ways and means to do it."

Secondary Principals' Association president Vaughan Couillault says the scheme is valuable and he's sure some schools on the cusp of eligibility would like to be included.

"I am absolutely certain there are people that are just the other side of that funding line that would like that line moved.

"From my experience the Ka Ora Ka Ako Healthy School Lunches Programme makes a real difference on the ground, so I can understand why they're hungry for it."

But Couillault says extending the scheme to all schools would result in valuable funding for disadvantage being used to feed children who are not disadvantaged and he's not sure that principals will support that.

-John Gerritsen/RNZ.