Graduates with unpaid student loans and absent parents who have skipped the country owing more than $300 million in child support could soon be nailed at the airport.
Revenue Minister Peter Dunne plans to introduce a bill in May to give the Inland Revenue Department access to customs declarations by international travellers.
The department will use reciprocal arrangements to get other countries to collect child support from New Zealand parents overseas, starting from the new addresses stated on their departure cards.
Officials at home will chase up liable parents and students when they come home for visits or permanently.
At this stage, the changes stop short of actually barring big debtors from leaving the country but Mr Dunne has asked officials to report on whether this could be done.
"We have relied on essentially individual honesty for people to tell us when they are leaving the country," he said. "We are now looking at improved data matching so we know it more accurately."
The National Party's shadow welfare minister, Judith Collins, said warrants should be issued to arrest all debtors at the border.
She said New Zealand's child support debts had been allowed to spiral out of control to $1.1 billion as at last June. At the same date, Australia's child support debt was only A$899.5 million ($1 billion) for a country with five times New Zealand's population.
"If they can stop fines defaulters at the airport, why can't they tackle some of the parents who owe thousands upon thousands of dollars for the support of their kids?" she asked.
In June, 123,000 out of 172,000 paying parents (72 per cent) owed debts on their child support. Of those, 18,755 (15 per cent) were believed to be overseas.
Those who had left the country owed 36 per cent - far more than their fair share - of the debt.
In March 2005, debtors living in Australia alone owed $299.3 million, or 33 per cent of the total debt at the time.
Last September, there were also 27,620 people with New Zealand student loans living overseas, owing a total of $666 million.
Ms Collins said New Zealand should consider passing full child support payments on to custodial parents on the domestic purposes benefit (DPB). At present, only $151 million of the $341.3 million collected is paid to custodial parents, while the Government takes the remaining $190.4 million to offset the cost of the DPB.
Just under half of the custodial parents, 86,600 out of 177,500, were on the DPB at the end of December.
Australia and Canada pay the full child support payments on to custodial parents, giving liable parents an incentive to pay up because they know their money actually goes to their families.
"That's not party policy," Ms Collins said.
"It's something I would look at in terms of whether or not it's feasible and whether or not taxpayers can afford that."
However, Mr Dunne said that proposal was "not as pressing as some of the other issues".
He said three-fifths of New Zealand's child support debt was due to penalties imposed for late payment.
Many parents also objected to paying child support if they were sharing care of the children with the so-called "custodial" parent.
Mr Dunne has asked officials to prepare new rules on how much child support should be paid in such cases.