A health and safety lawyer believes the Transport Agency has been too cosy with the rail operators it is required to regulate for safety and wants change.
Since a 2000 inquiry into the deaths of rail workers in the 1990s, health and safety in rail has been covered by two pieces of legislation - the Railways Act and the Health and Safety at Work Act, and overseen by the Transport Agency and WorkSafe when it was established in December 2013.
Now a report from the Rail and Maritime Transport Union has laid out the case for urgent reform.
In 2012, 10 KiwiRail workers were overcome with gas while working in the country's longest tunnel, the near nine kilometre long Kaimai Tunnel.
The workers lacked emergency evacuation equipment and did not have any procedures in place and there was no ability to communicate between the teams working in the tunnel.
In November 2013, there was a similar incident in Otira Tunnel near Authur's Pass.
Health and safety lawyer and author of the report, Hazel Armstrong, investigated these cases for the Rail and Maritime Transport Union.
She said the Transport Agency did not use its power to improve tunnel safety, but that the then newly-formed WorkSafe was prepared to issue improvement notices and enforce standards.
"NZTA had oversight for many years and did not, so, we had to rely on WorkSafe to issue the improvement notices and the prohibition notices, because NZTA wouldn't."
Ms Armstrong said the rail operators have been allowed to write their own rules as part of a light-handed approach to regulation and she had no confidence in the Transport Agency.
"We have seen many years of an approach or a culture within NZTA that is not robust around health and safety."
The union's general secretary, Wayne Butson, said it commissioned the report as part of an ongoing struggle to get rational health and safety regulations into the rail industry since the Railway Act came into force.
He said since that piece of legislation came in in 2005 not one rule had been written by the Transport Agency.
Mr Butson said the agency did not have a culture of regulation, "what they have is a culture of trying to encourage and educate and work with employers to see how they can improve safety".
"I think using the carrot without the stick just does not work."
Wayne Butson and Hazel Armstrong said rail safety and regulation needs to be completely taken out of the agency's hands and fall under WorkSafe.
The Transport Agency is under scrutiny for its oversight of other parts of the transport industry and it is now subject to an external review.
In a statement, the Minister of Transport, Phil Twyford, said he is asking for advice on what changes to the regulatory function are required and expects that rail safety will be looked at as part of that work.