E-scooters have been allowed on to footpaths and roads without the risk assessments a transport official has said were necessary.
Documents show the rule change to allow the vehicles onto footpaths went through just seven days after scooter operator Lime asked for it last September.
Auckland is beginning a new trial of up to 500 e-scooters by a second company, Wave, using scooters to be maintained by Lime's start-up billion-dollar rival Bird.
This comes after Lime resumed trials in Auckland and Dunedin, following a short suspension because of 150 cases of brake failure that injured 30 people.
Lime and Bird are both being sued in the US over injuries and parked scooters blocking paths.
In January last year, a New Zealand Transport Agency (NZTA) official warned there were "significant" risks if e-scooters could share footpaths and roads.
But NZTA went ahead anyway, saying it did not change any road rules to do so, just clarified them.
However, this contradicts its own documents.
The warning about the risks came in January 2018, in an Official Information Act response from NZTA to a member of the public.
"It would be a significant change in current classification for further small-powered vehicles not to be treated as motor vehicles," the official wrote.
"Any change would require considerable investigation and consultation into the appropriateness of making a change as there are significant possible risks in these vehicles using and sharing both the footpath and the roadway."
This was just months before Lime's launch with hundreds of scooters in several cities.
But NZTA has now told RNZ that the scooters had not been classed as motor vehicles, since a 2005 road user rule change allowed them to be used without entry certification, registration, warrant of fitness, or any driver licensing, under a status known as "wheeled recreational devices".
This contradicts the NZTA's OIA response in January 2018 that they were motor vehicles.
Similarly, in a notice issued by the agency said this "does not change the regulations governing the use of e-scooters, rather it clarifies their interpretation".
However, the notice, titled E-Scooters (Declaration Not to be Motor Vehicles), states: "The purpose of this notice is to remove the requirement for scooters ... to be registered as motor vehicles if they are also fitted with low-powered electric auxiliary propulsion motors."
An earlier notice from 2013 said: "For the avoidance of doubt readers are advised that the district court has held that low-powered electric scooters are not power-assisted cycles but are motor vehicles."
A Road User Rule supports the agency's assertion that e-scooters are "wheeled recreational devices" which are allowed on footpaths if they have motors under 300 watts and to which registration and licencing don't apply.
In 2018 an official said any change to classification, such as of e-scooters, would be significant and require considerable investigation and consultation. The agency said it had done no substantive research into e-scooters since 2004.
E-scooters imports have skyrocketed from virtually nil in 2011 to 25,000 last year.
A 2017 study NZTA commissioned focused mostly on e-bikes, with little about e-scooters.
The Ministry of Transport said in July it was reviewing footpath rules for vehicle use.
RNZ has the emails exchanged between Lime and NZTA, which is overseen by the ministry.
In one a senior NZTA official tells another that "Mike Williams (Labour Party) [is] asking the agency to write a letter allowing e-scooters to be used on footpaths in Auckland and Christchurch".
Mr Williams is a former Labour Party president. In the exchange he told NZTA he was seeking advice on behalf of Lime.
A day later, on 11 September, Lime emailed NZTA saying it was lodging an official request to reclassify its e-scooters as non-motor vehicles.
It said it intended "to launch in Auckland and Christchurch by September 20 ... urgency is requested".
NZTA replied within minutes, calling Lime's ride-share model "quite exciting" and saying: "As mentioned on the phone, your timeline is very tight; we'll see what we can do ... [but] be assured we are working on it now."
Then, three days before the notice came out, NZTA still did not have confirmation.
However, an official emails Lime to say: "Fingers crossed, by mid-next week you can quit worrying about the legality of the e-scooters and focus [on] other things like the launch."
NZTA has not returned calls for comment on this story.
Road researcher Dr Glen Koorey said anomalies in road regulations were not unusual and could compound over the years. In this case, those anomalies were cleared up quickly and in a way that is working out well for e-scooter companies.