Ava Seculovic's father Michael pays tribute to the teen after she died following Perth e-scooter crash

A young girl who died after an e-scooter crash has been remembered as a cheeky kid with a beautiful smile.

Ava Seculovic, 13, was crossing Wanneroo Road at the intersection of Dundebar Road, in Perth's northern suburbs at 2pm on Friday last week when she was struck by a car.

She was rushed to Perth Children's Hospital with life-threatening injuries.

WA Police said the teenager had died in hospital.

Ava's father Michael Seculovic paid tribute to her in a post on social media.

'I know you because I love you, thank you for everything ... I will talk to you in time.'

A fundraising page has been set up to help the family cover funeral costs.

'Her kind nature, beautiful smile and cheeky nature will live within us forever,' the post read.

CCTV footage shows the girl crossing the road as a white 4WD approaches.

The driver of the car was not injured.

Police said the investigation is ongoing by the Major Crash Investigation Section.

Meanwhile, a 12-year-old boy remains in a critical condition after he was hit by a car while running across a regional road that same day.

He was struck by a Toyota Prado on Caves Rd, in Marybrook, about 5.40pm.

The boy was flown to Perth Children's Hospital where he remains in a critical condition.