Absent fathers would put pressure on solo mothers to get out of their obligation to pay child support under proposed changes to welfare, the National Party says.
The Government is reviewing the welfare system, but has already signalled that it plans to remove the penalty for a solo parent, usually a mother, who refuses to name the other parent.
"We know that has had a negative impact on the woman and the child," Social Development Minister Carmel Sepuloni said at the weekend.
She said that there was no evidence that the penalty - between $20 and $30 a week - had any impact on absent parents paying child support.
But National Party deputy leader Paula Bennett, who oversaw a review of the welfare system as social development minister, said the changes would let absentee fathers off the hook.