The Council of Trade Unions (CTU) is calling for an appeal to be launched after the Waitakere District Court ruled that the death of a young security guard is not the responsibility of his employer.
Charanpreet Dhaliwal was found dead on his first night working as a security guard on a construction site in Henderson in November 2011.
The man accused of killing him was last month found not guilty in the High Court.
Now, his employer CNE Security has been cleared of a charge of failing to secure the 22-year-old's safety.
But CTU President Helen Kelly says the decision is wrong.