In a rare move, the Council of Trade Unions is taking legal action against two forestry companies over the deaths of workers.
A series of coronial inquests was due to begin in May this year into eight recent deaths in the logging industry, but some of those hearings are now on hold to allow for possible court action.
The CTU says there have been 32 forestry deaths since 2008. It wants to prosecute two companies in relation to two cases that WorkSafe investigated but never laid charges over.
CTU president Helen Kelly told Radio New Zealand's Nine to Noon programme on Tuesday that safety systems in place are paper-thin. "One worker can make a mistake and therefore they can be blamed for their death."
Ms Kelly said council has applied for permission to prosecute and it should be granted.
Ona De Roy from WorkSafe New Zealand told the programme she could not comment on why the regulator didn't prosecute.
However, she said since the organisation started a campaign on forestry safety in August last year, at least 25 crews have been told to stop work immediately because of concerns.
Ms De Roy said WorkSafe is concerned by the level of non-compliance throughout the country.
A lawyer specialising in workplace safety said WorkSafe has been afraid to take risks and needs to take more prosecutions against companies who breach safety legislation.
Hazel Armstrong believed it should be tougher. "They're the enforcement arm, unsafe operators have to know that prosecutions may well follow if they're found out."