A gang of Sudanese teenagers allegedly bashed an autistic boy, 17, in an horrific attack on a Melbourne bus on Saturday.

Max, 17, was travelling alone on the bus at Tarneit, 25km west of the CBD, when five Sudanese men approached him and told him to hand over his mobile phone and shoes.

When Max refused, the gang attacked him, kicking him in the head so hard he suffered a concussion and required a CT scan to check for permanent damage, his mother said.

Max, 17, was travelling alone on the bus at Tarneit when five Sudanese men allegedly approached him

Max's mother Julie told 3AW on Tuesday her distressed son called him in tears.

'He said "mum I'm scared",' Julie said.

'It has taken a lot out of him because he doesn't want to go on public transport again.'

Julie said she immediately drove to meet her injured son where the bus pulled over at Tarneit McDonald's.

Within minutes, she said the group of five Sudanese men grew to a group of about 30.

Within minutes, she said the group of five Sudanese men grew to a group of about 30 at the Tarneit McDonalds

A spate of criminal activity has swept across Melbourne in the past 18 months, with a series of car-jackings, armed robberies and home invasions, blamed largely on the notorious Apex gang

Julie said Tarneit was 'overrun by Sudanese' people and claimed they often gathered at the local McDonald's.

She said reports of violent behaviour from young Sudanese men in the area left her feeling scared for her son and the larger Melbourne community.

'It's not safe for anyone, let alone for someone with a disability, they put so much trust in everybody,' she said.

A spate of criminal activity has swept across Melbourne in the past 18 months, with a series of carjackings, armed robberies and home invasions, blamed largely on the notorious Apex gang.

Apex gang members are primarily from a Sudanese refugee background.

Apex gang members are primarily from a Sudanese refugee background (two members pictured)

Julie called on the Victorian Premier Daniel Andrews to take action.

'For Christ sake, just open your eyes and see what's going on around you, there will be more than one life taken soon,' she said.

'My son was lucky he got out of it the way he did.

'When is the Government going to wake up? I'm very angry, very very angry.'