The total number of "lost time injuries" at the Port of Tauranga over the financial year ending March 31, 2011, was less than 20 per cent of those at Ports of Auckland, he said.
But the opposition's spokesperson for Labour, Darien Fenton, said she was concerned at how the "increasing casualisation of New Zealand's workforce was undermining health and safety".
She backed the Maritime Union's claims that Port of Tauranga casual workers were often scared to report accidents or safety concerns, fearing they would be punished with fewer hours of work.
"All workers should be able to speak up about safety concerns and report accidents. If this doesn't happen, the changes necessary to improve safety and reduce our workplace death and injury toll won't happen," Ms Fenton said.
New Zealand's death and injury toll at work was four times greater than comparable countries. Forty-one Kiwis died at work last year and 6000 were seriously injured. In addition, thousands of workers died from occupational disease.