A Dunedin log truck driver may be charged after the trailer of a loaded truck he was driving disconnected and ploughed through a barrier on State Highway 88, down a bank and into water at Blanket Bay.
The incident happened about 6.20am yesterday when the truck was being driven towards Port Chalmers from Dunedin.
No-one was injured despite the potential for a disaster, Senior Sergeant Steve Aitken said.
"We are lucky it happened when it did and not an hour later when there was a lot more traffic on the road. Had it occurred later in the day it could have been pretty disastrous," he said.
Police were investigating the cause of the incident, which was initially termed a ring feeder failure.
"We need to determine the cause of the ring feeder failure. If it was a mechanical fault there wouldn't be charges but if there was some operator error, i.e. it wasn't connected properly, then it's possible there would be a charge," Snr Sgt Aitken said.
The driver heard a bang and thought he had lost a log, but then realised the trailer was gone.
The Dunedin Carrying Co Ltd trailer was winched out of the water by a tow truck about 1pm.
SH88 was closed to one lane for a few hours during the recovery.
The rail bank prevented the logs off the trailer from floating into Dunedin Harbour before eventually being removed from the water.
Dunedin Carrying staff made no comment when approached by the Otago Daily Times at the crash site yesterday.
A staff member at the company's Dunedin office said "the bosses" were not available and could not be contacted until today.
Yesterday's crash renewed concerns about the stretch of highway between Port Chalmers and Dunedin, and its use by heavy vehicles.
In March last year, a logging truck and trailer unit tipped on SH88 near St Leonards, hurling 20 logs like torpedoes across the road.
No-one was injured and damage was minor, but the incident frightened road users and residents who called for change.
Last month, submitters to the Otago Regional Transport Committee bemoaned the dangerous nature of the road, especially for cyclists.
The committee recommended an allocation of $220,000 in the 2012-13 financial year for a New Zealand Transport Agency study, which would include consideration of creating hub rail capacity on the KiwiRail network south of Dunedin.
Recommendations for the transport plan will be considered by the Otago Regional Council in a couple of weeks.