"It was pretty scary for them, but there's no way any one could have foreseen this happening. It was in broad daylight, in a public car park that was highly visible," she said.
The offender is described as male Maori, skinny build in his 20s or 30s.
He is short and is said to have a wispy goatee. He was wearing a blue hooded sweatshirt with a black leather vest over the top.
The vest also had a patch on the back of it.
Police are asking anyone who sees this vehicle to phone 111 immediately.
If you know who may be responsible you are also urged to contact Police or by phoning Crimestoppers on 0800 555111.