"While cutting concrete, the saw bounced off a pipe and into his throat, slicing it clean open. After surgery, it's a miracle he is alive today.
"A freak accident occurred that makes you appreciate how precious life can be."
It is understood the victim, aged in his 20s, was working on one of the building sites.
A hospital spokesman said the patient was in a stable condition but would not reveal the extent of the injuries or how the accident happened.
"The plan is for discharge tomorrow," he said.
Robbie Walker, a spokesman for St John ambulance, said the patient was picked up from Robert Might Rd about midday in a moderate condition and taken to North Shore Hospital.
It is understood he was quickly transferred to Auckland City Hospital where an ear, nose and throat specialist operated on him.
The hospital spokesman said the patient was now intent on returning to his home.
A spokesman for Worksafe, the Government's workplace health and safety regulator, said no reports had been made about Monday's accident. WorkSafe advises caution when using high-speed saws which it says on its website are "designed to cut the toughest materials used in the construction industry".
"Typically, diamond saw blades and cut-off discs have a surface cutting speed of approximately 300km/h."
Power tool injuries and deaths
November 2014: An angle grinder became embedded in engineer Mark Nathan's chest after it kicked back while he was working on a Dannevirke sawmill.
October 2014: Three men were injured while operating a concrete-cutting saw in Christchurch. A wall was being cut at the Lyttelton Working Men's Club when some of the workers fell but they escaped with moderate injuries.
March 2014: 16-year-old Mitre 10 worker in Glenfield lost two fingers while using an industrial saw.
July 2013: Hawkes Bay builder Robert Barr died after accidently shooting himself in the chest with a nail gun while working on a rural property in Waipukurau.
April 2013: Builder John Terence Hebden, the owner of JT Hebden Building and Construction, died when the blade from an angle grinder he was using shattered and a segment embedded itself in his abdomen, at the back of his work premises in Christchurch.
January 2013: Worker at VIP Frames and Trusses in Christchurch shot in the chest with a nailgun by another employee.