A man is fighting for life and two young children have been injured after an Uber and van collided in Melbourne's inner city.

Five people were rushed to hospital after reportedly being injured in the crash about 3.45pm on Sunday.

Victoria Police say one adult is in a serious condition, while the second adult and the two children all suffered injuries.

A preschool-aged child was thrown from a pram after the car hit nearby pedestrians.

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A man is fighting for life and two young children have been injured after an Uber and van collided in Melbourne 's inner city

Five people were rushed to hospital after reportedly being injured in the crash about 3.45pm on Sunday

Victoria Police said a 'share car' lost control after being struck, and hit a number of pedestrians on the street corner and hit cars waiting at nearby traffic lights.

The exact cause of the collision is being investigated and the drivers of both vehicles are assisting police.

The crash involved a Royal Automobile Club of Victoria van.

The two children are at Royal Children's Hospital Melbourne. A hospital spokeswoman said the older child is in a stable condition while the younger child is in a serious condition.

Victoria Police say one adult is in a serious condition, while the second adult and the two children all suffered minor injuries

Sydney woman Nicole Brown was in the passenger seat of the Uber when it collided with the van at the intersection of William Street and La Trobe Street.

'We went to turn, when suddenly a yellow RACV van came up on the inside lane and clipped the car… we lost control,' she told Nine News.

'We started spinning and took out all these people.'

Detective acting sergeant Mark Kelly said the driver of the van rad a red light, and is now cooperating with police.

'The scene was chaotic but it was well managed by all emergency services,' he told news.com.au.

'The driver stopped immediately and is very co-operative. He's obviously in shock.'

He said police believe the crash was accidental.

Sydney woman Nicole Brown was in the passenger seat of the Uber when it collided with the van at the intersection of William Street and La Trobe Street

Witnesses at the scene claimed an Uber driver attempted a U-turn moments before the crash.

Investigations into the crash are ongoing, and there are expected to be charged laid against the driver of the van.

Two of the adults have been taken to the Royal Melbourne Hospital, while the other adult has been taken to St Vincent's Hospital.

An RACV spokesperson said they are 'very concerned for the health and wellbeing of all the people involved in the accident'.

'RACV will offer any relevant assistance where we can.'

More to come