A young boy has been bitten on the cheek in front of horrified shoppers during a brazen daylight robbery at a Sydney shopping centre.

Deklan Manley, 13, was with a friend at Macquarie Shopping Centre on Herring Road in Sydney's north at about 11.30am yesterday when two men approached him in what police believe to be a random attack.

One of the men threatened him and attempted to steal his shoes before the boy pushed him away.

Video of the scuffle was posted to social media. (Supplied) (9NEWS)

Police are hunting for a man (left) they believe can assist them with their inquiries. (NSW Police) (NSW Police)

The man is described as aged between 18 and 20, between 170 and 175cm tall with short blonde hair and a tattoo of the letter 'K' on the back of his left hand. (NSW Police) (9NEWS)

Deklan Manley was at Macquarie Shopping Centre with a friend when he was approached. (Instagram/deklanmanley_) (Instagram/deklanmanley_)

Deklan was then assaulted and bitten on the cheek.

He managed to escape his attackers and was treated for his injuries at a nearby medical centre.

Police say the "brazen" daylight attack is out of the character for the area.

"The motivation for the actual incident at this stage we are not aware of - we believe it was a random attack," NSW Police's Acting Superintendent Jason Weinstein said.

"We don't believe the young person was themselves targeted for any reason apart from having some clothing on them."

Police have obtained mobile phone vision of the assault as well as CCTV from the shopping centre and say it is "only a matter of time" before the suspect is caught.

A spokesperson for Macquarie Shopping Centre confirmed the "unfortunate incident", saying the centre's security were on the scene immediately and police were notified.

"Unfortunately an incident occurred at Macquarie Centre which resulted in a customer being assaulted and subsequently requiring medical attention," the spokesperson said in a statement.

"The safety and welfare of our customers, retailers and employees is our top priority and we continue to assist police with their enquiries."

The two men attempted to steal Deklan's shoes. (Instagram/deklanmanley_) (Instagram/deklanmanley_)

Police say it is "only a matter of time" before the suspect is caught. (NSW Police) (9NEWS)

The 13-year-old was treated for his injury at a nearby medical centre. (Instagram/deklanmanley_) (Instagram/deklanmanley_)

Macquarie Shopping Centre has confirmed the "unfortunate" attack. (Google Street View) (Google Street View)

Police are appealing for public assistance to track down the man believed to be behind the assault.

The two men who approached the boy have been described as Caucasian in appearance, aged between 18 and 22 and between 170 and 180 centimetres tall.

The man police believe to be behind the attempted robbery has blonde, short and shaven hair and a tattoo of the letter 'K' on the back of his left hand. He was last seen wearing a grey hooded jumper, green cargo pants and a black baseball cap.