Ports of Auckland's lawyer, John Billington QC, said: "The port accepts full responsibility for this tragedy."
But Harrison said it is the ratepayers of Auckland who are paying for management failures.
"Until those managers who have a duty of care to their workforce are prosecuted for recklessness under the Health and Safety at Work Act, we will continue to see a culture of profit before safety."
Dyer was working a night shift on August 27, 2018 when the freight-carrying straddle vehicle he was driving tipped and crashed.
The 23-year-old was critically injured and died a week later.
The court heard today that Ports of Auckland, which pleaded guilty to one charge under the Health and Safety at Work Act 2015, had a bonus scheme to reward straddle drivers for high productivity.
Harrison said the union had opposed the bonus system, which contributed to the culture at Ports of Auckland.
WorkSafe prosecutor Barbarella McCarthy said Ports of Auckland had failed in its training of straddle drivers, particularly when taking a turn at speed and the "tip alarm" was activated.
Dyer had a high tip alarm rate but consistently received his bonuses, the court heard today.
Harrison said the union also raised concerns over the driving culture, which included ignoring tip alarms and using cellphones, which management had been aware of before Dyer's death.
Dyer had been using a mobile phone and was not wearing his seatbelt on the night of his accident.
Harrison said the port's management was aware how the straddle carriers were operating because the vehicles automatically reported safety incidents.
However, following an objection from the union, Ports of Auckland did not use CCTV cameras in the straddle cabs to monitor compliance and the use of cellphones and wearing of seatbelts.
"Instead, due to the height of the straddle cab, [Ports of Auckland] was reliant upon other individuals, who were working at height, to report any non-compliance," the court's agreed summary facts reads.
The port had also sought to reduce tip alarm activations with a training program, however, despite success, this was ceased and on the night of Dyer's death tip alarms were back to earlier levels, the court heard.
It was only after Dyer was killed that management took steps to change the culture, Harrison added.
McCarthy also told the court some drivers did not pay attention to the tip alarm and there was an inaccurate understanding of when the warning sounded, the straddle would automatically apply its brakes.
Dyer's death is one of two workplace fatalities at Ports of Auckland in as many years.
In September, Auckland Mayor Phil Goff announced an independent review of health and safety at the ports, which is Auckland-Council owned.
Port worker and father-of-seven Palaamo Kalati died at the port in August.
Harrison said the Government must widen the inquiry to a national level and look at how productivity pressures and fatigue were killing workers.
In November, Ports of Auckland announced it was also undertaking an organisational review, which includes an investigation into the accident that killed Kalati.
