Detectives investigating the vicious machete attack on a teenager who had his $10,000 e-bike stolen have released graphic photos as they seek public help to find the offenders.

The attack occurred “without warning” when the 17-year-old was approached by two unknown men around 6.15pm on June 20 at JW Manson Reserve in the Melbourne suburb of Wantirna, according to Victoria Police.

“As the victim tried to run away, he was hit from behind with a machete, causing a deep wound to his shoulder,” they said in a statement released on Friday.

The teenager, who has since turned 18, managed to flee onto nearby Selkirk Avenue and stop a passerby, who called triple zero.

He ended up spending four days in hospital with at least three injuries and required surgery.

The teenage victim required surgery for his injuries. Photo: Victoria Police

“This unprovoked and senseless attack on the victim is extremely concerning and completely unacceptable,” Detective Acting Inspector Troy Andrews said.

“Investigators have been working tirelessly in relation to finding those involved and to hold them to account for their actions.”

The attackers stole the teenager’s Surron Ultra Bee HP e-bike, said to be valued at around $10,000, as well as his mobile phone.

The attackers stole the teenager’s e-bike. Photo: Victoria Police

In addition to photos showing his injuries, detectives have released CCTV vision show two males they believe can assist with their inquiries.

Police have increased their presence in the area since the attack, with Andrews saying they are “patrolling the community 24/7”.

Anyone with information is urged to contact CrimeStoppers on 1800 333 000.