Two teenagers have been hospitalised after a birthday party at an Airbnb property in Sydney’s south-west descended into a violent brawl involving around 70 people, prompting a major police response and renewing questions about unauthorised parties at short-term rental properties.

Emergency services were called to a home on Zephyr Street in Austral shortly after midnight on Sunday after reports that two people had been assaulted during what witnesses described as a chaotic confrontation.

When officers from Liverpool City Police Area Command arrived about 12.05am, they encountered a large crowd gathered outside the property but were initially unable to locate the injured victims, who had already left the scene.

A short time later, police found a 19-year-old man suffering stab wounds to his torso inside a vehicle on nearby Browns Road in Austral. At almost the same time, another patrol located a 17-year-old male with stab wounds to his thigh in a vehicle on Fletcher Street in Middleton Grange.

NSW Ambulance paramedics treated both teenagers before they were transported to hospital in stable condition. Police have confirmed an investigation into the double stabbing remains ongoing.

According to investigators, both victims are believed to have attended a birthday celebration being held at the short-term rental property when violence erupted after uninvited gatecrashers allegedly arrived at the gathering.

Authorities believe the confrontation rapidly escalated into a large-scale fight involving approximately 70 people, creating what neighbours described as an extraordinary scene of violence in an otherwise quiet suburban street.

“I’d probably describe it as a war,” one nearby resident told television reporters after witnessing the disturbance.

Video recorded during and immediately after the incident has since emerged showing the aftermath of the violence. CCTV footage reportedly captured the two injured teenagers stumbling along nearby streets after being stabbed, while separate footage showed police arriving at the property as officers attempted to disperse crowds.

The vision also showed an African woman being restrained by police while another officer deployed pepper spray toward a group of males during efforts to restore order.

Detective Inspector Scott Houldin described the scene as chaotic, saying police were forced to deal with a rapidly evolving situation involving dozens of people before emergency medical treatment could begin. Police have confirmed pepper spray was used after officers encountered resistance while attempting to secure the area.

Investigators recovered multiple knives from both the property and surrounding streets. Those weapons have been seized for forensic examination as detectives attempt to determine exactly how the stabbings occurred and identify those responsible.

Despite the size of the disturbance, no arrests have yet been made.

Police are reviewing CCTV footage, mobile phone recordings and other available evidence while appealing for witnesses or anyone with additional footage to contact Crime Stoppers.

The property where the party was held was being rented through Airbnb, despite the platform maintaining a global ban on parties at its accommodation listings.

The home had been advertised online as a relaxing family getaway suitable for quieter stays rather than large social gatherings.

According to the property’s owner, guests requested that security cameras be switched off before they arrived at the residence. The circumstances surrounding that request are expected to form part of inquiries into how the gathering unfolded.

While invitations to the birthday event were reportedly not made publicly available, they were later shared across social media, allowing many more people to learn about the party than organisers had originally intended.

Police believe the arrival of gatecrashers significantly increased tensions before the situation escalated into widespread violence.

The incident highlights the ongoing challenges facing short-term accommodation providers and homeowners attempting to prevent unauthorised parties at rental properties.

Airbnb introduced a permanent global ban on disruptive parties following a series of serious incidents internationally and has since implemented restrictions on certain bookings considered higher risk. The company also uses automated systems designed to identify reservations that may be associated with unauthorised gatherings.

Despite those measures, police across Australia continue to respond periodically to incidents where social media has transformed relatively small private celebrations into much larger events attracting uninvited guests.

In many cases, investigators say rapid crowd growth increases the likelihood of confrontations, particularly where alcohol is involved or organisers lose control over attendance.

NSW Police have not publicly stated whether alcohol, drugs or existing disputes between attendees contributed to Sunday’s violence.

Nor have detectives identified any suspects or indicated whether those responsible for the stabbings were known to the victims.

The investigation remains in its early stages, with detectives continuing to interview witnesses and analyse forensic evidence recovered from the scene.

Police have urged anyone who attended the gathering, captured video of the incident or possesses relevant dashcam footage to contact Crime Stoppers as investigators work to establish exactly how the confrontation unfolded.

Anyone with information that may assist the investigation is encouraged to contact Crime Stoppers on 1800 333 000 or submit information online. Police have reminded members of the public not to report crime information through social media channels.

For nearby residents, the incident has left lingering concerns after a suburban birthday celebration ended in serious violence that required a significant overnight emergency response.

As detectives continue their inquiries, authorities hope witness statements, CCTV recordings and forensic analysis of the recovered weapons will help identify those involved and determine whether further criminal charges will follow.