Iain Duncan Smith has condemned the "madness" of the state subsidising poor families to have large numbers of children.
The Work and Pensions Secretary said it would be fairer to the "vast majority" of responsible taxpayers if benefits were limited to the first two children in future.
The comments came as Tory ministers eye another £10 billion of savings from the welfare budget by 2016 - on top of the £18 billion already made.
Interviewed on BBC Radio 4's Today programme ahead of a speech on the issue, Mr Duncan Smith said he was tackling an ingrained culture.
"We have accepted for far too long in this country that it is possible for people to just stay on benefits and we write them off," he said.
"It's no surprise that we are in massive debt and huge deficit because we are not paying our way.
"It is all about saying, we will give you massive support to find work, we've obviously got to help you and support you and get you right.
"But also, we have an expectation as the taxpayer pays for these bills that you seek work, that you try your hardest to find work. If you don't want to do that then there are penalties to be had. There is a balance here.
"You can't just sit there and gather more and more on benefits. Benefits should be, for many people - unless you are chronically sick - a temporary place, a place you then move on (from) and into work."
"This is madness. It is madness also for the taxpayer," he added.