There are more than 3000 large families with five children or more on the benefit. One-third have been on the benefit for more than five years and 430 for more than 10 years.
Bennett said there were some people, such as grandparents and foster carers, who had taken children into their care who were doing a valuable duty for the community - but others who were taking advantage of the system.
Welfare researcher Lindsay Mitchell said the domestic purposes benefit was seen by many as a "default" lifestyle.
"If you're a young woman with no qualifications, no work skills and no work experience, your income prospects aren't great. The DPB easily surpasses anything she would get with her skills."
Mitchell said there would always be people who found loopholes in the system, despite the effort to get mothers back to work when their child turns 6. "When you start putting pressure on someone to get a job, one option for that person is to have another child [to qualify for the DPB again]. You get more money, it becomes an incentive."
But beneficiary advocate and former Green MP Sue Bradford said everyone would be better off if beneficiaries received more money.
"Do the maths on it and have a bit of compassion. Anyone who calculates how much it costs to feed and clothe those kids will know how hard it is," she said.
She feared what negative effects Bennett's policies could have. "The costs will be exponentially bigger - family violence, justice, prison, police, hospitals. Crime and ill health are natural consequences of poverty."
And Mangere East Family Service Centre chief executive Peter Sykes said it was unwise for any government to shake up the social welfare system without a transition process.
All up, the Government would typically pay around $1150 a week to a parent with eight children, $1215 a week with nine children and $1276 a week with 10 children. Accommodation supplements and special needs grants were examples of extras available which would have some families above $2000 a week. These figures are more than double the national median income for an individual, which is $550 a week ($28,600 a year).
Last year, 3868 women on the DPB - around four per cent - had another child. This excluded women younger than 18 years and those who had been on the DPB for less than 42 weeks when they fell pregnant.
Work and Income's deputy chief executive Debbie Power said most beneficiaries wanted to work. "Generally, larger families will be eligible for more support, but not in every case." .
Woman's daily struggle on $1000 welfare benefits
Catherine has nine children under 15 and a husband who comes and goes. Given her large family, she's entitled to around $1000 a week in social welfare and gets subsidised rent on a five-bedroom state house in South Auckland.
The law allows her to collect a weekly domestic purposes benefit of $293.58, an accommodation supplement of $225, a family tax credit of more than $600.
She might sometimes claim additional hardship assistance and a temporary benefit top-up of $88 a week.
Some may accuse her of having an easy life, but Catherine faces a daily struggle to feed her family.
The reason she cannot make the books balance, says Mangere Budgeting Services chief executive Daryl Evans, is because she is in hock to predatory money lenders who demand huge repayments each week.
Her debt, inherited from her partner, is upwards of $45,000.
Much of it is representative of high-interest and fees rather than money borrowed.
By the time the rent and bills are paid, little is left for day to day survival and when the money runs out, she is forced to buy groceries from the mobile food trucks that roam poor neighbourhoods.
They charge $7.95 for two litres of milk and $5 for a loaf of bread, but her credit rating means she doesn't have access to credit cards that a supermarket would accept.
"In an ideal world," says Evans, "she would be working but currently there aren't any jobs. They simply don't exist."
As the 11th child born into a poor family, he is familiar with the harsh reality faced by large families on the bottom rung of the social ladder.
He pulled out of the poverty trap and now teaches financial management skills to people like Catherine. But he says there are not enough community groups funded to support those who are struggling. He says: "It's that idea of 'teach a man how to fish and he can feed himself for a lifetime'."
