The talented young swimming champion was on her way to practice at the local pool when she was struck by a Ford Laser as she crossed Hillsborough Road in Warners Bay just before 5pm.

She sustained significant head injuries and broken bones, said Highway patrol Superintendent Stuart Smith.

Paramedics treated her at the scene before taking her to John Hunter Hospital in a critical condition.

Olympian swimmer Thomas Fraser-Holmes posted a message of support to his Facebook page on Wednesday: "My heart is deeply saddened to hear the news about Jade Frith today. My thought & prayers go out to you and your family. #novocastrian stay strong".

But Jade died on Thursday afternoon.

Grief-stricken friends and family shared their sorrow on Facebook, using the hashtag #capsoutforjade to post photos of their swimming caps and goggles as a tribute to the talented swimmer.

Dozens of love hearts fill the comments of her Facebook profile picture, with several posts reading "fly high little one" "...angel" "...beautiful".

"We as a club are mourning the death of a brilliant swimmer from Novas Swim Club, Jade Frith", posted Hunter Valley Allstars Swim Club.

Local community sporting groups pledged to observe a minute's silence, or don black armbands during their weekend competitions in honour of Jade.

The driver of the car, a 22-year-old woman, was not injured.

Officers from Lake Macquarie Local Area Command are investigating the incident and will prepare a report for the Coroner.