The driver managed to get out of the truck and was being treated by St John paramedics when firefighters arrived.
The driver, from Whangarei, of the logging truck escaped unhurt.
The driver's seat of the Mainfreight truck was seen laying in a drain beside the badly mangled vehicle, which is a write-off. Debris, including papers, were strewn for about 100 metres across the southbound lane.
Southbound cars were diverted via Springfield Rd in Oakleigh while the northbound ones through Salmon Rd in Waipu.
Since the diverted route was windy and unsuitable for bigger vehicles such as logging trucks and buses, they were allowed to travel through SH1 with a stop-go sign at the crash scene.
Mr Ewers said the impact of the crash was massive and the Mainfreight driver was very lucky to be alive.
"We don't believe speed was an involved but fatigue could have been an issue but that will become more clearer one we complete our investigation," he said.
Police have described the stretch of SH1 between Oakleigh and the Brynderwyn as a "death trap" because of the number of serious crashes and fatalities over the years.
Last December, a French tourist who arrived into the country just hours before died in a three-car smash just north of yesterday's crash.
A month earlier, a 64-year-old Englishman, who had also arrived in the country on the same day, died after a head-on smash near the intersection of Totara Rd and SH1 at Oakleigh.
