The mother-of-two knocked down in a hit-and-run outside a Melbourne shopping centre has died in hospital from her injuries.

Andrea Lehane was left with "unsurviveable brain damage" after she was allegedly hit by a teenage boy on a "monkey bike" motorcycle as she crossed a pedestrian crossing in Carrum Downs on Thursday shortly after 5pm.

The 34-year-old mother was taken to the Alfred Hospital where she was pronounced dead on Friday evening.

Three teenage boys handed themselves into police after executing a number of search warrants in suburbs east of Melbourne following an investigation by Major Collision Investigation Unit detectives.

The group of four or five motorbike riders hit mother-of-two while she was on a pedestrian crossing before fleeing the scene shortly after 5pm on Thursday evening.

"The boys, a 16-year-old from Carrum Downs, a 17-year-old from Seaford and a 15-year-old from Carrum Downs, are assisting Major Collision Investigation Unit detectives with their enquiries," police said in a statement on Friday afternoon.

View photos Andrea Lehane with her husband James Lehane. Source: Supplied More

"Police executed a number of warrants at houses in Carrum Downs, Seaford and Frankston today."

The 17-year-old Seaford boy was charged with reckless conduct endangering life, reckless conduct endangering persons, unlicensed riding and unregistered vehicle.

He was bailed by police and will appear at a children's court at a later date.

The 16-year-old Carrum Downs boy is expected to face the same charges while the 15-year-old remains in custody.

A fourth boy from North Frankston was interviewed by police on Thursday night and later released. Police are still searching for a fifth boy possibly involved in the incident.

Ms Lehane suffered "unsurviveable brain damage," her husband said.

Ms Lehane's family confirmed her condition as they kept a vigil at her bedside at the Alfred Hospital.

Ms Lehane, whose children are aged three and four, has been described as an "extraordinary wife, mother, daughter, sister, aunty, niece and friend".

Flowers left where mum of two Andrea Lehane suffered fatal injuries at Carrum Downs shops on Wednesday. #7newsmelb pic.twitter.com/ieLWWuD4y2 — Paul Dowsley (@pauldowsley7) September 25, 2015

Her husband, James, has released a statement saying his wife would not survive the accident.

"On Wednesday afternoon my family's lives changed in an instant from a careless and avoidable accident," he said.

"As a result of the impact, my wife suffered unsurvivable brain damage.

"The team at The Alfred have done an extraordinary job, but the damage has been confirmed to be too great.

"Being a nurse, Andy was always keen on organ donation, so as a family we have consented to her going through a complete organ donation process.

"Some time today or tomorrow she will go into theatre, with her life support machines, for her final act of caring and giving.

Sequence of events

View photos First motorbike, pcitured left of screen, speeds past the woman as she begins to walk over the marked pedestrian crossing. Photo: CCTV More

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