Miliband said that the plans, which were announced at the Conservative Party conference earlier this month, were particularly hard on families where one parent chose to stay at home.
"Why should a family on £45,000 a year where one person stays at home lose their child benefit but a family on £80,000 where both people in the couple are working should keep their child benefit?" said the Labour leader. He added: "That doesn't strike people as fair, it doesn't strike me as fair. Why does it strike the PM as fair?"
Cameron defended the measure saying that "as we deal with the deficit we do have to ask better off people to bare their share of the burden. We spend £1bn giving money through child benefit to relatively better off homes. We think that has to change".
In reference to Miliband's status as a higher rate taxpayer, Cameron added: "There are thousands in his constituency who earn a sixth of what he earns. Through their taxes they will be paying his child benefit. Is that fair?"
