The Government is reviewing how child support payments are calculated because of anomalies in the system.
The Minister of Revenue, Peter Dunne, says the system does not take into account the income of a mother's new partner.
Mr Dunne expects to seek public input on the issue by August.
Coalition of Fathers spokesperson Jim Bagnall says child support is an inflexible system which fails to calculate how much it costs to raise a child.
He says thousands of families are struggling to meet payments, and some fathers are at their wits' end, or even suicidal.