Plumber pulled alive from collapsed trench

Rachel Gray
AAP

A plumber has been pulled alive from a trench after rock and dirt collapsed on him at a worksite north of Sydney.

The 45-year-old man was pinned from the neck down before his quick-thinking workmates pulled him to safety just after midday on Friday in the Sydney suburb of Terrey Hills.

The man suffered suspected neck, chest and pelvic injuries and was treated at the scene by a CareFlight specialist doctor and critical care paramedics.

He was then transferred by road in a serious but stable condition to Royal North Shore Hospital.

NSW Ambulance Inspector Andrew Rienits said emergency services did all they could but it was the quick and decisive actions of the man's workmates that saved the day.

"We were on scene within minutes but the patient had luckily been retrieved by his colleagues," Mr Rienits said in a statement.