Concerns are growing over rising CBD crime as Adelaide’s city centre sees more workers and shoppers caught in dangerous and unpredictable behaviour.

In two separate incidents on Wednesday, a teenage worker at Hungry Jacks was allegedly assaulted and a bystander injured during a police chase of a wanted man.

WATCH ABOVE: Man dramatically arrested in Adelaide CBD after allegedly assaulting police

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One incident unfolded as police chased a wanted man through Rundle Mall before he was tackled to the ground on nearby Pulteney St.

Witnesses watched two officers sprint after the 23‑year‑old for several hundred metres before half a dozen more joined in to restrain him.

Police said the Rosewater man was wanted on an outstanding warrant and over a robbery last month.

He was also allegedly carrying a flick knife, a balaclava and multiple driver licences in other people’s names.

A female bystander was caught up in a dramatic CBD arrest falling and hitting her head. Credit: 7NEWS

He’s been charged with providing a false name, hindering and resisting police, assault, assaulting a prescribed emergency service worker, carrying an offensive weapon, unlawful possession and other traffic offences.

During the struggle, an innocent woman was struck and hit her head on the footpath.

“During the grabbing, I think they hit her at the same time,” witness Harry Wu told 7NEWS.

“I reckon the guy getting arrested was shouting because he probably got injured as well — but not the lady. She’s a tough one.”

Paramedics treated her and two officers before taking them to hospital.

The man was refused police bail and will face court on Thursday.

Fast food workers targeted in separate incident

Hours earlier in a separate incident, fast food workers were targeted at the Hungry Jack’s on Pulteney St.

Police say a man jumped the counter early Wednesday morning, allegedly assaulting a teenage worker before fleeing with food.

Officers then tracked down the suspects walking through Rundle Mall.

A 30-year-old man and a 34-year-old woman were arrested. The man has been charged with assault and theft and was refused police bail.

The woman was charged with disorderly behaviour.

Both will appear in court at a later date.

The Shop, Distributive and Allied Employees Association (SDA) says the latest attack shows CBD staff are being left exposed.

“To make sure those employers are doing everything they possibly can to keep their workers safe from these whacked‑out individuals that keep coming in and causing harm,” SDA secretary Josh Peak told 7NEWS.

The union is calling for security screens across city outlets, similar to those already installed at a nightclub hotspot at the Hindley St McDonald’s.