Casual workers at the Port of Tauranga say they are too scared to report accidents and injuries for fear their employer will blacklist them for future work.
The union representing port workers, the Maritime Union, says casual workers fear they will be overlooked for work if they report being injured on the job.
They also claim shortcuts are taken at the port that endanger workers.
Port chief executive Mark Cairns strongly rejects the accusations.
"It's absolute rubbish. We have had a real strong drive over the last year and our goal at the port is for zero harm. That's no injuries at all and we have had really good progress with our own staff."
Port of Tauranga has one of the lowest claims history with ACC out of all New Zealand ports.
The Department of Labour said there were five serious harm incidents at the port in 2011. This includes the death of Fulton Hogan worker Walter Crosa, who was hit by a grader while tarsealing in August.
Port of Tauranga's Maritime Union organiser Selwyn Russell said it was not uncommon to have accidents involving "digits, little bits of fingers, arms and sprained ankles".
"But I don't think you will see them in the paperwork."
Russell said casual workers often took whatever hours they could and did not want to lose their chance of getting work by speaking up.
"It's real concerning. Everyone's really worried about what will happen if they report something. I know people who have hurt themselves but didn't say anything because they might not get picked," he said.
Russell said "near misses" happened every shift at the port.
"It's like working on a motorway, there is so much congestion."
His union has 225 members, mostly employed on the Mount Maunganui side of the port. Organised labour on the Sulphur Point container terminal was mostly covered by the Rail and Maritime Trade Union.
He said the turnover of casuals on the wharves was significant.
Rail and Maritime Transport Union lead delegate John Carmine said the issue was "a bit of a problem in some ways".
"It's pretty hard for the casuals because they don't want to turn down work because they are trying to get a permanent job."
Carmine was a casual worker for three years.
The RMTU is the main union on the Sulphur Point side of the port, and regularly approached their employer to create permanent jobs for its members who had worked significant regular hours.
A casual worker at the port, who spoke on the condition of anonymity for fear of losing work, said no one wanted to rock the boat and miss out on income.
"The environment is really competitive. It's dangerous. It's hazardous. You have machinery operating, you have noise, you have the ships sort of swaying side to side and the logs are like torpedoes."
The worker said casualisation of the workforce meant everyone competed for shifts, including many men with families to feed.
When faced with reporting an injury the general consensus was "oh nah, keep your head down and do the job".
"But when you are loading a ship and another company is fumigating a bunch of logs 10m away, it's not that safe."
The worker said although there were health and safety procedures in place, short cuts were often taken because it was not possible to stick to safety rules and load ships in time.
"You are continuously under pressure to get the ship loaded and out as soon as possible. Because the industry is so competitive, you have companies competing for contracts and that all comes down to time.
"It makes it quite a dangerous place to work. I'm not saying the bosses are horrible but they are squeezing us. Because you are casual you are forced to take what shifts you can ..."
This was usually in the form of "rolling shifts", resulting in tired staff with a dangerous environment, the worker said.
Casual workers at the port make on average nearly $20 an hour before tax.
Cairns said the union appeared to be "mischief-making".
He sent a letter to port stakeholders earlier this year about the port's health and safety procedures, encouraging the reporting of near misses.
"If you aren't reporting those, you can't do anything to improve the place," he said.
"My door is always open ..."