Mr Cunliffe said some schools had used "dubious tactics" to tap parents for cash, including repeatedly sending children home with letters and, in one case giving children 'donation paid' tags to attach to their bags.
"Labour does not believe children should be discriminated against and ostracised because of their parents' financial situation."
Schools received $97 million in donations in 2012 with parents of students at higher decile schools being asked for bigger donations.
However, the donations were particularly hard on low income communities with decile one to three parents contributing $10 million a year, Mr Cunliffe said.
Under Labour's plan schools would still be able to charge "activity fees".
Figures released to the Herald in May showed parents were raising more than $357 million a year in donations and fundraising to support the "free" schooling system.
The mother of two students at Auckland's decile 10 Meadowbank School told the Herald she paid two lots of the $480 annual donation requested by the school and then an additional $167 in activity fees.
"If you don't pay your donation or you part-pay, your child gets an envelope to bring home about once a term to ask for payment - ie they are named and shamed."
At the time, Education Minister Hekia Parata said donations were not compulsory, and boards of trustees decided upon what parents were asked for. "That's up to each school and their parents. They need to be talking about those expectations."
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