The chair of the agency, Lester Levy, said he raised questions about Lime scooters' safety as far back as October and asked Auckland Transport to urgently review the conditions of their trading licence.
"From the outset, I have had serious safety concerns, initially about user behaviour, but recently we're seeing what could be equipment - either software or mechanical failure. I am very concerned," he said.
"I think we should have a formal safety case that is created beforehand that is considered with due diligence by all the relevant organisations that are critical to this."
Not wanting to be seen as limiting innovation, Dr Levy said "cool" had trumped "safety".
Several people have been catapulted off the e-scooters due to a braking fault that randomly locks up the wheels. Lime has until the end of the week to prove the fleet's safety.
Lime's response is too slow, he said.
"I've asked our chief executive at AT in his involvement to alter the threshold of this. If we don't get responses quickly, in my view they should take more severe action which could involve curtailing the trial."
Lime was introduced under a trading in public places bylaw, which is an Auckland Council and Auckland Transport bylaw.
Checkpoint, then told Dr Levy that behind the scenes, former Labour Party president and lobbyist Mike Williams had smoothed the way for the Lime roll out.
Mr Williams confirmed to Checkpoint that he was paid by Lime to introduce their representatives to Auckland Transport staff and another key contact - Transport Minister Phil Twyford.
"I'm quite uncomfortable with many aspects of this," Dr Levy said.
Auckland Transport staffer Wally Thomas is believed to have met with Mike Williams and a Lime executive from the US on 26 July 2018 at Auckland Transport 's offices.
In November, post Lime's launch, Mr Thomas, Auckland Transport 's chief executive, and a safety manager met with Mike Williams and Lime's New Zealand representative. It was at Auckland Transport's request to discuss safety concerns including limiting scooters speed.
Checkpoint invited Mr Williams, Mr Twyford and Lime for an interview. All three declined.
Now, Dr Levy is looking into a "deeper, wider" investigation.
"The burden of proof should be on Lime, unless they can prove with immediacy there is no problem, then they should be removed."