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The recommendation was included in his finding into the death of two young people in a shearing-van crash at Poolburn two years ago.
He said the major contributor to the deaths of Stewart Hetaraka Smith (20) and Lavenia Setefano (19) was their failure to wear seat belts.
They were part of a shearing gang heading into the Ida Valley for work on September 18, 2008, when the van they were travelling in left the road and rolled, 4km east of Poolburn.
They were thrown from the vehicle and died at the scene.
The driver, Pagan Rimene, of Alexandra, admitted charges of careless driving causing injury and careless driving causing death and was sentenced to 300 hours' community work last June.
She was also ordered to pay $7000 in emotional-harm reparation and disqualified from driving for 18 months.
Mr Crerar said it was the legal responsibility of adults to use a seat belt in a vehicle but he had anecdotal evidence of "general neglect" in the use of seat belts by shearing-industry employees.
"I do not know why there is the reported reluctance by employees in the wool harvest industry to use seat belts, but they fail to protect themselves at their peril."
Employers should enforce seat-belt use, with reference to the matter in workers' employment contracts, he said.
He suggested the person in charge of each crew of shearers and woolhandlers, who usually drove the vehicle transporting them, should not start the vehicle until all employees had their belts fastened.
"I repeat, the obligation would be under the employment contract as well as under the Transport Act."
Mr Crerar has also asked for a national review of the safety of vehicles transporting employees to and from work and said employers should be encouraged to use the safest possible vehicles and ensure drivers were trained appropriately.
"The focus of the inquest hearing [in Alexandra on November 11] was the need for employers - and specifically those engaged in the wool-harvest industry - to ensure appropriate work and travel practices for their employees," Mr Crerar said.
His findings were sent to the New Zealand Shearing Industry health and safety committee, the Department of Labour, the Minister of Labour and the New Zealand Transport Agency.
The issue of vehicle safety should be addressed by the shearing industry and the appropriate government agencies, he said.
The Smith and Setefano families had questioned whether a person with a restricted licence should have been driving the shearing gang that day and also questioned the suitability of a Toyota Previa as a vehicle for transporting shearers.
Mr Crerar found the vehicle was "as suitable as any and more suitable than most vehicles being used in those circumstances".
The vehicle came through the crash with its structure relatively intact.
The coroner said he was satisfied Mr Smith and Miss Setefano would have survived had they been wearing seat belts.
"I trust that the recommendations I have made will bring comfort to the whanau and will have an outcome of a safer work environment for the shearers and woolhandlers of New Zealand."
Asked to comment on the findings, acting Southern District road policing manager Senior Sergeant Steve Larking said a seat belt was the "simplest and easiest piece of safety equipment to use that can save your life if you're in a crash".
The failure of drivers and passengers to wear seat belts contributed to deaths and injuries on the roads time and time again, he said.