Malcolm Hey urged cabinet member for transport Lynne Stagg to end the Voi-operated scheme in September in comments made at her decision-making meeting on Thursday.
'These e-scooters are a danger to riders themselves to pedestrians and to other road users alike,' he said. 'It might be okay to use them in the wide boulevards of California but certainly not in the cramped streets of Portsmouth.'
Cllr Stagg was recommended to convert an experimental traffic regulation order which has been in place since March last year into a permanent one from September, once its 18-month limit is reached.
The decision to approve the new order will allow the trial to continue until its scheduled end in late November, although this deadline is expected to be reviewed with the potential for a further extension.
In May, the Department for Transport wrote to the council confirming it would introduce legislation for a new ‘low-speed, zero-emission vehicle category’, legalising the use of e-scooters beyond the trials being run by councils.
Under the current rules, they can only be used on public land through these insured schemes.
Last month government ministers also agreed to allow councils to extend their trials until May 2024.
Cllr Stagg said she 'took the points raised' by Mr Hey, particularly around concerns with the use of privately-owned e-scooters but said Voi's strict definitions of the severity of injuries meant concerns the scheme had been overblown.
'Their definition of serious accidents isn't most people's definition of serious accidents,' she said, citing an example of someone who fell off a machine and did not require treatment but was classified as a serious incident because a passerby had called an ambulance.
'It makes it sound a lot worse than it really is,' she added.
'I'm happy to go along with [the permanent order] because it will give the government time to get the legislation in place which is desperately needed.'
However, following a suggestion from the Conservative opposition spokesman for transport Scott Payter-Harris, Cllr Stagg also agreed that another consultation would be held before any decision was taken to extend the trial beyond November.