Revenue Minister Peter Dunne said the current system focused too heavily on penalties and people were not coming forward to IRD to make payments.
"What happens is people get behind in their payments and they incur interest and penalties and the figures get to be very huge and they drop out of the system because it becomes all too difficult,'' said Mr Dunne.
Father of two Scott Lewis said it wasn't good enough to have to wait for the changes to come into place.
"It's not fair from where I'm sitting''.
He has shared custody of his two children with his ex-wife. He has care of his children half of the time and pays $700 a week in child support payments.
New Zealand had a mutual agreement with Australia for child support payment cases and the law would make it easier to deal with unpaid child support.
"We are updating the scheme to fit today's social realities,'' Mr Dunne said.
The changes will bring New Zealand in line with Australian policy.
New Zealander Paul Jenkins killed himself in Australia last year after receiving a demand for over $53,000 of child support arrears relating to his daughter from a previous relationship.
IRD used its powers to request the Australian Child Support Services Agency to collect the outstanding debt.
Labour MP David Cunliffe said the National Party had been working on the issue for 10 years and should have tackled child poverty when looking at child support.
"Despite all of the time the Government has failed to provide an improved system that is transparent, fair and flexible and that will address the situation of the 133,000 kids growing up in poverty in single-parent families, most of whom are dependent upon child support,'' he said.
The bill is awaiting its third reading.
