Mother-of-one Melissa says she is facing an impossible situation, required to pay an ever-increasing amount of child support.
She pays nearly $300 a week for her teenage son on an annual salary of just over $87,000.
"I absolutely cannot afford this, I am in severe hardship and considering resigning from my career… I am extremely worried about my future."
She said while her salary might sound high, it was hard to cover costs as a single person and she had been on ACC for a long period after a serious accident. It also meant that she did not qualify for any additional assistance.
It felt like every time she asked for help, the amount she was told to pay went up, she said,
"I cannot hold up a home for my son anymore and am moving into a flatting arrangement… I am mentally struggling with being forced to do this, my son deserves better… It's the only choice I have left… if the cost of living wasn't where it's at right now and the cost of housing, that would possibly be different. It would still be unfair but it might not be crippling me in the way it is now."
RNZ has chosen not to identify her to protect the identity of her child.
Melissa said she suspected her former partner had artificially made his income seem low so that she would be required to pay more, and was living in a house owned by his partner. She felt he was not willing to discuss a private arrangement, she said.
She said they had been involved in expensive ongoing court proceedings for years about who should have care of their child.
"He has worked and manipulated me and made me pay for leaving - a decision that was not made overnight and wore very heavy on me.
"I ran out of money… I'm stuck in a parenting order that was null and void a year or two years ago, because of that, I've got this child support noose around my neck.
"They're saying the only way is to go back to a lawyer… And they just keep putting it up."
The parenting order gives care to her son's father, but Melissa said the effort she put in for travel for her child and additional expenses she paid for were not taken into consideration.
She is one of a number of parents who have been in touch with RNZ, expressing concerns about the child support system.
When parents do not have a private support agreement in place, child support is worked out based on the child's age, the parents' incomes and living situations, the amount of time a child is in each person's care, the cost of bringing up a child and the cost of any other children the parent might have.
Each parent is given a living allowance that is updated each year and an allowance for children not having child support paid for them.
Inland Revenue's calculator shows that in the 2026 tax year, someone earning $120,000 a year with a child in her care six nights a week and an ex-partner earning $150,000 with the child the other night could receive about $14,374 a year in child support.
Divorce coach Bridgette Jackson said child support calculations were a major concern for people she dealt with - both among those who felt they were being asked to pay too much and those who felt they were receiving too little.
"There needs to be an overhaul. I am regularly seeing parents who are shocked by what the IRD says they've got to pay and on the flipside, parents really frustrated at how little they receive."
She said it was particularly an issue when care arrangements changed.
"If a parent ends up doing extra overnights, the support amount doesn't actually automatically update and can feel really unfair until they apply for the assessment and who knows how long that assessment is going to take."
Parents often said that the formula did not reflect real life expenses, she said.
"The identity shift for some parents… they move from being an involved parent to feeling like they're paying and they feel like they've lost their worth or the loss of a role, they feel a loss of control because the amount is set by a formula which can feel really inflexible.
"Many people are adjusting to a single household and all the costs that come with that. They feel child support is the last straw. Especially if the other parent seems better off or care time isn't reflected accurately, it can feel unfair."
People who had a pay cut would sometimes have to keep paying based on last year's higher income until a reassessment happened, she said.
"There are a lot of high earning parents paying very little because of the way they've structured their companies or trusts. Or the creative accounting with a low salary.
"The system needs a shake-up and it needs it fast. .. there needs to be better income transparency especially for people who are self employed or using companies or trusts… there needs to be plain language guidance so everyday parents know their rights without these huge legal costs."
Bill Atkin, a family law expert and emeritus professor at Victoria University, said the formula for calculating child support was revised by a law passed in 2013 that came into force in 2015.
"It made several changes, for example by taking both parties' income into account instead of just the payer's and reflecting the shared nature of day-to-day care more than the original formula.
"The system is run by the Inland Revenue Department and, given that it is a mathematical-like calculation, it can usually be done easily and cheaply via a computerised system.
"However, it is a somewhat blunt instrument and cannot automatically take account of every possible variable. So, there will be outcomes that people, whether they are payers and recipients, find difficult."
People could object, for example if their income had been wrongly factored in, he said.
"The other process allows people to apply for a departure, for example on the grounds of their capacity to pay, duties owed to others like other children, or the income, earning capacity, property, and financial resources of either parent or the child.
"A departure is not always easy to obtain as there must be special circumstances. Initially, a departure is determined by an administrative review but ultimately it can be determined by a court.
"So, the formula is somewhat arbitrary but there are checks and balances for situations where the formula is a really bad fit."
At the end of March, child support debt was $930 million, which was 10% lower than the same time a year earlier.
"For the first time in 20 years, child support debt dropped to under $1 billion," a spokesperson for IRD said.
"The primary reason for that is IR's ability to deduct payments through the PAYE system - 76 percent of child support assessments were paid on time - up by 5 percent from the same time in 2023 resulting in $182m being passed on to receiving carers."
