School principals say a review of the school decile system is urgently required.
Three Wellington principals have told Radio New Zealand's Outspoken programme that the system for providing targeted funding to schools with students from poor families was not meeting their needs.
They have welcomed the Government's suggestion the system could be reviewed, saying change was overdue.
The deciles divide schools into 10 groups based on the proportion of their roll that comes from poor neighbourhoods, as measured by indicators including income, household overcrowding and qualification levels. Schools in decile one have the highest proportions of such students and get the most funding per student, while decile 10 schools have the lowest proportions and get the least government funding.
The system is used to allocate about 11 percent of total government funding for school operations, not including teacher pay.
Three Wellington principals have told Radio New Zealand it is imperative the Government finds a better way of helping schools to support disadvantaged students.
The principal of mid-decile Newtown School, Mark Brown, said a review needed to happen as soon as possible.
"It's exceedingly urgent. Well overdue. And I think it's a challenge for this Government along with their Children's Action Plan to start addressing this immediately and in a robust way otherwise we will continue to talk about this and debate it in, say, three or four years' time."
The principal of decile one Porirua College, Susanne Jungersen, said her school used its decile funding to provide extra support for students and to make up for shortfalls in areas such as special needs.
But she said it was not enough.
"It really helps, but it isn't sufficient, because the way that children are impacted on coming from poor households is multi-layered. It's like a thin rubber band that's stretched to sort of screaming point and every bit of funding does help, but it is insufficient."
Ms Jungersen said there would be less need for the targeted funding delivered under the decile system if the gap between rich and poor were not so big.
She said that was the core problem the Government needed to address.
"If you actually allowed every family to gain a living wage, and we reduced the inequality gap in New Zealand and we poured all our efforts into that, you wouldn't need this patch up job called targetted funding."
The principal of decile 10 Wellington Girls College, Julia Davidson, said the decile system was too blunt.
She said her school got very little decile-related funding and relied on donations and fund-raising to meet the needs of students from disadvantaged backgrounds.
Ms Davidson said it might be better to tag extra funding directly to individual students.
"Until you get to a system where money is attached to a student, it's going to be a problem. If there was a really clear piece of work done that identified families in need, and therefore it didn't matter which school those children went to, X money came with them, that might be a fairer way of doing it."
The principals warned that the school system was complicated, and any replacement of the decile system would have to be carefully thought through.