The Government ignored concerns from health officials before announcing plans to cut benefits to parents who did not keep up to date with health checks for their children, Labour says.
Labour's Social Development spokesperson Jacinda Ardern says documents released under the Official Information Act show Ministry of Health officials feared the effectiveness of the WellChild programme would be harmed by the new measures.
She said they advised that introducing mandatory checks risked undermining the programme and the reduction of benefits might hurt the health of the families.
Under new welfare reforms announced in September and due to be implemented next July, parents will also be required to complete core WellChild/Tamariki Ora checks, and if they struggle to comply with the obligations, could be referred to support services.
Those who fail the obligations will get three reminders before up to 50 percent of their benefit is taken away.
Social Development Minister Paula Bennett says the move is "in the interests of the child".
Ms Ardern says 95 percent of children born each year are enrolled in the WellChild programme and health officials were keen to improve the delivery of the programme to those who were not taking full advantage of it.
She accused Ms Bennett of ignoring advice.
"[She] has once again allowed politics to come before evidence-based policy and advice."