The Children's Commissioner says it should be illegal to hold kids in adult police cells.

Figures from Amnesty International show 165 under-18-year-olds who had been arrested were held in a cell over the last year, awaiting a court appearance.

Commissioner Andrew Becroft says they should be in youth justice facilities.

He told Mike Hosking police cells are harder to visit, and for youth to access education - and there's a real risk of harm by suicide.

"It's been something of an enduring blight on our system for the last 30 years or so. We could remove it really with the stroke of a legislative pen."

LISTEN ABOVE AS ANDREW BEYCROFT SPEAKS WITH MIKE HOSKING