"She is demonising these families when she has been told over and over again by various ministries that her social obligations and work obligations will cause more harm."
Ministry documents highlight that 22 per cent of early childhood services have recently had waiting times of more than three months for 3 year olds.
A lack of suitable supply for those in poor areas was also identified as a major hurdle.
However, Social Development Minister Paula Bennett said such advice also made clear that beneficiaries would not be punished if all reasonable steps were taken to enrol.
That acknowledged that there were some situations beyond parents' control.
"I have been very clear, if parents are genuinely unable to meet the obligation to have their children in ECE, they will not be penalised for it."
However, Ms Turei said recent incidents had demonstrated that Work and Income New Zealand workers could not be trusted to judge what constituted "all reasonable steps".
On Monday, the Herald reported a woman's claims that she was told she could not buy tampons on a Work and Income food card because they were considered "luxury items".
"They [case managers] will take their lead from Paula Bennett, who is demonising these families. And they will make decisions which ... don't follow the policy but take a punitive approach," Ms Turei said.