The Children's Commissioner wants a rethink of universal services such as pensions and free children's healthcare so more public spending can go to the neediest families.
The commissioner, Hastings children's doctor Russell Wills, wants tomorrow's Budget to start a national "conversation" about how to use limited public spending to best effect.
"We need all taxpayers' funds to make the biggest difference they possibly can," he said.
"That might mean further targeting of some of those benefits that are currently universal.
"There are lots of examples of that, such as free healthcare under 13 for everybody, free early childhood education for everybody.