A WorkSafe investigator sent to Waikaraka Park after a photographer was hit and nearly killed by a stockcar was initially refused entry to the venue, the health and safety regulator claims.
And when the inspector finally gained entry, he and a colleague were allegedly blocked access to track bosses who WorkSafe say remained in the venue's hospitality area.
Photographer John Sprague was critically injured after being hit by a stockcar travelling at up to 80km/h on January 13, 2018.
Sprague was working near a large tyre which had been placed in the infield as a safety measure. He spent more than five months in hospital.
After the incident, a raft of speedway safety changes were initiated.
Documents released to the Weekend Herald under the Official Information Act show WorkSafe inspectors had problems at the venue on the night.
One inspector was "initially refused entry to the speedway venue by gate staff".
Once inside the Onehunga park, the inspector and a colleague were then "refused access by security staff to promotion officials, who were located in a corporate box".
Waikaraka Park president Frank Irvine rejected the claims, which feature in WorkSafe's investigation report.
He said he was in the venue's infield at the time, not the corporate area.
The venue's promoter and track manager Bruce Robertson said he was also aware of WorkSafe's access issues.
But he said: "They would be lucky to get in because the pit gate is locked once racing gets underway".
In terms of claims involving security staff, Robertson was also in the dark, adding he would not routinely spend much time in the venue's corporate area on race night.
"I might have gone into [the corporate area] for a minute or two but I run the meeting so I am in the infield, out at race control and all around the place," he said.
"I am certainly not located in there."
The investigation concluded that a prosecution could be considered against Speedway New Zealand under the Health and Safety at Work Act 2015 in that it "failed to manage risk arising from a work activity over which they exercise significant influence and control".
A peer reviewer of the investigation later wrote: "I agree that there is significant evidence of failures on behalf of SNZ. They have failed to assess and to manage a very obvious hazard (that they were well aware of) and that if realised, will inevitably result in serious injury or death."
But last December, prosecution plans were shelved. WorkSafe decided factors such as safety changes by SNZ, public interest, and the fact Sprague did not want any further involvement in the case meant court action shouldn't go ahead.
Changes introduced by SNZ include reducing the number of people allowed in infield areas, requiring them to get a safety briefing, and improved barriers.
That includes ensuring any person on the infield be behind a temporary barrier or in a vehicle. At Waikaraka Park, the tyre barrier has been moved further infield.
SNZ has worked with health and safety experts in its safety overhaul, which included the new infield management plan.
SNZ general manager Zoe Irons said that had involved a "huge amount of work".
"That wasn't an easy thing to develop as there are aspects to speedway in New Zealand which are unique to the rest of the world," she said.
Irons also said that the sport had some of the "best safety rules" in terms of global speedway, including around safety fences and other trackside safety equipment.
She said being proactive in terms of health and safety had become a growing factor in all sectors in recent years, including motorsport.
But she added: "All sport has elements of risk. There is always going to a risk involved in motorsport because of what you are dealing with, it is really just a matter of management of risk."
When asked what the message to member tracks was ahead of the 2019/20 season, Irons said: "Safety is a constant discussion, not just ahead of the season. And the sport will continue to learn and our focus is around the safety and education of our stakeholders."
Waikaraka Park has also recruited a health and safety officer.
Sprague was released from fulltime medical care on June 29, 2018. He has declined to comment.
The report revealed Sprague would not take part in the WorkSafe investigation adding that he and his wife "wanted to be left to get on with their lives".
It also revealed a photographer standing just metres from Sprague when he was hit also would not sign a statement which he had initially provided due to the "considerable distress that the incident caused him at the time, and the ongoing distress felt by him as a result".
The investigation report stated: "Footage of the incident shows the victim being thrown through the air, rolling across the ground, and coming to rest with no movement."
The report also revealed that a year before, Sprague and a witness to the crash were almost struck by another vehicle.
Two vehicles had crashed mid-race; the driver of one lost consciousness and their car passed "between the two, missing them by around three metres".