"We don't have the resources; in fact, some of them will comply without us checking them and we don't need to, so we take a subset," she told TVNZ's Q + A programme yesterday
Ms Bennett said the tests would apply only to 20,000 to 25,000 children each year.
Asked whether this would stigmatise the worst-off beneficiaries, she said: "At the end of the day, my focus is really, really firmly on those children. And I look at it and I go, 'If you know what we know, so we know the benefits of early-childhood education, we know that getting enrolled with a GP, having those well-child checks, is hugely beneficial for those children who are struggling most."
Ms Bennett also confirmed that not every child needed to attend a preschool. "I don't think every child actually needs to be in early childhood education, but I do think it benefits those that are most vulnerable so much. That's why I'm doing this."
Labour Party social development spokeswoman Jacinda Ardern said: "You either believe this works for every child or you don't ... I think she's changing her goalposts."