Work and Pensions Secretary Iain Duncan Smith has been accused of trying to "move the goal posts" on child poverty after he suggested it was a waste of money paying benefits to parents addicted to drink or drugs.
In a keynote speech, Mr Duncan Smith called for a new "multidimensional measure" of child poverty to operate alongside the existing income-based measure, to better reflect the reality of children's lives.
Speaking at the Kids Company charity in London, he argued that there was too much focus on moving families over an "arbitrary poverty line" without a proper understanding of the real problems they were facing.
"For a poor family where the parents are suffering from addiction, giving them an extra pound in benefits might officially move them over the poverty line. But increased income from welfare transfers will not address the reason they find themselves in difficulty in the first place," he said.
"Worse still, if it does little more than feed the parents' addiction, it may leave the family more dependent not less, resulting in poor social outcomes and still deeper entrenchment. What such a family needs is that we treat the cause of their hardship - the drug addiction itself."
His comments drew a furious response from anti-poverty campaigners who insisted that addiction was only a problem in a small proportion of families.
"The vast majority of families in poverty are struggling because they can't afford the basics - not because they are wasting cash on drink and drugs," said Matthew Reed of the Children's Society.
"We know from our extensive work with families that parents are doing their very best. Every day they are making harsh choices between heating their home, buying school shoes or putting a hot meal on the table. Stereotyping children and families struggling to make ends meet is not the answer."
Rhian Beynon of Family Action said: "We already have a child poverty measure - changing the goal posts will not benefit those families in and out of work struggling to keep their heads above water."
Claudia Wood of the think tank Demos added: "New poverty measures have to be effective at tackling poverty, and a policy that only focuses on the small minority of people with drug and alcohol addiction ignores the majority in need."