Some communities might not be able to afford the devices, which could ''exacerbate an already serious achievement gap''.
''There is a significant risk that this will affect the same students whose achievement we are most concerned about.''
Philanthropists, community trusts, local government, public private partnerships, and targeted government funding were possible funding options, the paper said.
Children were more likely to look after a device if their parents had a financial stake in it, the paper said.
Green Island School principal Steve Hayward said pupils whose families could not provide a device used one provided by the school when necessary.
About 80% of year 7 and year 8 pupils brought their own, since the school introduced a bring your own device policy last year for that age group.
It created unexpected issues, such as pupils needing a device on a day it was also required by their father at work.
''That was something we hadn't really expected.''
He believed a digital divide in schools could increase the gap between the rich and the poor.
No pupil at Green Island School was going without a device when they needed one, he said.
Schools had many demands on their funds, and some would find it impossible to fund devices, he said.
Fundraising for them meant applying to community-based trusts and charities, whose ''funds were getting tighter each year''.
Abbotsford School principal Stephanie Madden said the school used the proceeds of its last fair to buy 30 iPads.
The school planned to investigate introducing a bring your own device policy.
Ministry of Education head of student achievement Dr Graham Stoop said in a statement the ministry expected access to devices would improve as their cost continued to reduce.
''As schools adopt digital devices, they are using a range of ways to ensure no student misses out; for example, by purchasing class sets of devices, or working with local charity trusts to purchase devices for sale to parents/whanau on lease-to-buy arrangements.''
Dr Stoop said there was no evidence to suggest a lack of access to digital devices was widening the achievement gap.
The ministry initially refused to release the mid-2013 document, requested in February, but released it in December saying it had reconsidered.
In September, the Office of the Ombudsman started an investigation into the ministry's decision to withhold that and other documents.
