Nearly $1 billion in child support is now owed by absentee parents as the number of broken families in New Zealand skyrockets.

A Ministry of Social Development study estimates one in two mothers will, at some stage, raise their children alone — a trend the Government says is reflected in the $873 million owed in child support.

The figure represents a 19 per cent increase on the amount owed 12 months ago.

Associate Revenue Minister David Cunliffe acknowledged the level of unpaid debt was unacceptable.

However, he blamed the 20% increase on more broken relationships resulting in more child support payments.

“As IRD (the Inland Revenue Department) deals with more people and greater amounts over time that debt is likely to increase,” he said.

National Party social welfare spokeswoman Katherine Rich said the Government should apply more “aggressive measures”, such as blocking parents who owed “reasonably-sized” child support debts from leaving the country through greater links between the Inland Revenue and Immigration departments.