More than 500 Northland workers have been seriously injured on the job in the past three years.
EPMU Northland organiser Andrew Bourke said some employers were reluctant to deal with serious health and safety issues.
Common workplace accidents in Northland included falls from a height, while five workers were badly hurt from contact with electricity.
Twenty-five workers were badly hurt in motor vehicle accidents, 15 suffered serious injuries after being hit, struck or bitten by a person and four others were seriously hurt after being deprived of oxygen, or suffocating.
Figures released by the Ministry of Business, Innovation and Employment show nearly one in four injuries was caused by falls, trips or slips.
Mr Bourke said that while some Northland employers take workplace health and safety seriously,- "it's the few that don't who ruined it".
"In Northland, we have the good, the bad and we have the downright ugly."
Guyco Timber Ltd, trading as Northern Pallet & Timber, was fined $50,000 when a worker had his thumb and forefinger amputated by an unguarded saw blade. It was the largest health and safety prosecution case in the region during the three years to August 2012.
Nationwide, 16,468 serious harm workplace accidents have been reported during the past three years.
At least 20 workers have died on the job this year.
A prosecution can result in a fine of up to $500,000 or a two-year prison term if an employer is found guilty of failing to ensure a safe work environment.
Fishing company Sealord was fined $63,400 last week and ordered to pay reparations of $12,500 to a fisherman who fell through a hatch and ruptured his spleen on the Ocean Dawn in October 2011.
The largest penalty imposed during the past three years was on Kiwi Steel NZ, - ordered to pay $237,500 in March 2011 after failing to report that two workers had the skin stripped from their fingers, one worker had part of their finger amputated and another broke his foot when a piece of steel fell on it.
The Employers and Manufacturers Association said many employers took health and safety seriously.
"Employers invest a lot of time and money in their businesses and their staff are the business," occupational health and safety manager Paul Jarvie said.
