About 305,000 - or 29 per cent - of our children live in poverty.
They grow up without access to the basic necessities of life, and carry the scars of poverty throughout their lives in preventable diseases such as rheumatic fever, cellulitis and respiratory infections.
These sanctions make that poverty worse.
So why would a mother not name the father of her child?
The key reason is violence. Our country has the highest rate of reported intimate-partner violence in the developed world. Police attend 110,000 family violence callouts every year.
Domestic violence victims are commonly also rape victims. The control exerted over them by the violent partner includes both forced sex and the partner determining whether the woman can have access to contraception.
Such men threaten women with further physical violence if they disclose paternity to Work and Income. Some women are physically beaten to keep them silent.
Incest victims may also be too scared to disclose paternity.
Section 177 of the Social Security Act provides that the sanction should not be applied if the beneficiary or children would be at risk of violence, or in cases of incest or sexual violation.
That sounds good in theory, but is miles away from what happens in real life.
The threats and violence exerted by a violent partner are far more powerful than the sanctions imposed by the Government. Further, many women do not even know they are receiving a sanction.
In order to have the sanction lifted, they have to obtain a letter from a lawyer. I used to write these letters when I worked in a Community Law Centre.
It is deeply humiliating and stressful for abused women to meet with a complete stranger and be asked intimate questions about the circumstances of conception. That is what lawyers have to do in order to provide the letter to MSD.
It is also normally difficult and expensive for mothers to find lawyers to do the letters - very few lawyers are familiar with this law, or provide these letters.
The Social Security Appeal Authority told the Ministry of Social Development in 2010 that it should not be making women get letters from lawyers. It said it was common sense that "if a woman is unable to name the father of her child she cannot establish who is in law the other parent."
The authority recommended that MSD change its policy on requiring lawyers' letters, but MSD has disregarded that recommendation and is still requiring the letters.
The sanctions are also a double standard. The Government in the 2015 Budget announced it would write off up to $1.7 billion in child support penalties. Between 2008 and 2014, Inland Revenue wiped $5b in tax debt. Up to $6b is lost every year through tax evasion. These are huge sums of money.
If the Government is concerned about its financial position and about obtaining additional revenue, it is clear that focusing on closing loopholes in other areas would bring in far more money than sanctioning sole mothers does.
At a time when the Government has made reducing domestic violence a high priority, these sanctions run utterly counter to that. They actually place women and children in danger. The current rewrite of the Social Security Act is a good time to abolish the sanctions altogether.
• Catriona MacLennan is a barrister and supporter of the AAAP campaign Stop the Sanctions.
