The collective had requested more information from the council to inform a legal opinion on whether to seek a judicial review of the decision.
"We're still awaiting legal advice, but if the advice is that we have a reasonable chance of success, we would be very willing to take that action", he said.
The collective has accused the council of failing to consult properly, failing to take into account social and economic impacts, and using unreliable parking data from Covid-19 alert level 2 in 2020.
But the council's transport and infrastructure manager Brad Singh said the parking changes were included in Let's Get Wellington Moving consultation.
Singh noted the collective was also given the opportunity to make both written and oral submissions to council.
"We are comfortable that we followed a robust consultation process which met the requirements of consultation under the Local Government Act and we are now implementing the decision made by council."
He said analysis of three data sets from 2017, 2019, and 2020 showed the remaining parking was expected to meet existing needs based on average occupancy rates.
Robinson said parking has always been a key proposition for businesses on Thorndon Quay.
"You can come and do business with us because car parks are readily available.
"There's no way in the world you're going to catch a bus into town to pick up 40 litres of paint and take it on a bus."
A childcare centre, bridge club, and dance studio were also affected, Robinson said.
"It's unlikely that mothers are going to catch a bus with their children going to the dance studio or parents are going to catch public transport to a childcare facility to drop their children off- that's not realistic."
The council's Environment Committee deputy chairwoman councillor Tamatha Paul said the council needed to make courageous decisions, that may be unpopular, to reduce carbon emissions.
She said she understood that tradies and people doing DIY were not going to carry materials and tools on a bicycle.
"It's not about expecting absolutely everybody to shift modes, we just want as many people who don't need to be in private vehicles to not be in them."
Paul pointed out there would still be 202 car parks for those who needed them.