As many as nine teenagers are on the run after allegedly stabbing a young father in the neck outside his north-west Sydney home.

David Sidhom, 29, approached a group of teens partying outside his home in The Ponds just after 9pm yesterday, and asked them to keep quiet.

A brawl occurred, and Mr Sidhom was stabbed three times in the neck during the altercation.

David Sidhom was stabbed in the neck after asking a group of teens to quieten down. (9news)

The 29-year-old was rushed to Westmead Hospital for emergency surgery. (9news)

The teens, believed to be eight males and one female, fled in two cars evading the police helicopter and dog squad.

Mr Sidhom was rushed to Westmead Hospital for emergency surgery for his injuries, which paramedics said could have been catastrophic.

"One (wound) was up to almost 15cm long and really, really deep," paramedic Joe Ibrahim said.

"From the amount of blood loss and from the difficulty controlling the bleeding it was obvious it was very deep.

"It could have very well, if it was too far forward, severed his trachea or breathing tube and if it was just a little to the left he could have ended up a quadriplegic."

A bloodied towel at the home today. (9news)

Neighbours said the park has been the site of rowdy gatherings in recent weeks. (9news)

Police said Mr Sidhom had simply asked the teens to quieten down.

"A reasonable request and it's escalated to this life-threatening incident," Inspector Glenn Jacobs said.

Mr Sidhom and his family had only moved into the street just over a year ago after buying a dream house to call home.

Neighbours told 9News rowdy gatherings in the park are a regular occurrence and residents have been too afraid to confront those in attendance.