Private prosecutions are being taken against the police and Corrections Department over two high-profile cases.
Victims' rights lobby group the Sensible Sentencing Trust is taking the legal action under the Health and Safety Act.
It relates to the actions of the convicted murderer Graeme Burton, and to the death of a Nelson woman in a car crash involving a repeat offender.
The action has been filed against both departments and senior staff.
Trust spokesperson Garth McVicar says it's not about money, but about ensuring that lessons are learnt from the tragedies.
He says the first hurdle will be court action in July to allow the private prosecution to proceed, even though it has been filed outside the usual six-month time limit.