The boy, whose name was not reported, was spotted driving in his pajamas by other motorists early Friday morning in Wellington, The Dominion Post reported.
Another driver blocked the boy and called police.
When officers arrived, the boy, who was crying by this point, told them he was having trouble sleeping and went out to visit his friends.
The police took the boy home and scheduled a meeting with the boy's parents and a Child, Youth and Family staff member for later this week.
"It's definitely not every day that minors as young as eight are behind the wheel. However, this is of concern to us and we are liaising further with the boy's parents to ensure he is aware of the risks involved," acting Wellington emergency response manager Paris Razos said.