NZ Bus is defending the 17,663 fines it received since October for late or cancelled buses, saying it had 150,000 services run on time.
The MP based in Rongotai - where the company's depot is - Paul Eagle, said the figure is outrageous and NZ Bus has to go.
"Anyone who's receiving that amount of complaints should really do the decent thing and say that's it, we're out of here.
"I was shocked when I was told that number. I think NZ Bus owes the ratepayers of Wellington an explanation."
Mr Eagle said NZ Bus should hand the buses back to Wellington ratepayers.
"They purchased them, all you do is run them, you need to do the decent thing and hand them back," he said.
NZ Bus chairman Kevin Baker said it was sorry for the late and cancelled services but it was committed to getting on top of things.
"Of course NZ Bus would prefer to be operating at a higher level of performance and lower abatements, and is working extremely hard to pull whatever levers it can to do so.
"Unfortunately the short planning period in 2018 and shortages of drivers in the Wellington market (both of which has been referred to since mid year) means that there are gaps in services compared to the full schedule, which have been agreed and are understood by GWRC [Greater Wellington Regional Council]," he said.
"NZ Bus is committed to returning to the high level of service it has been known for and all of its people including drivers, duty supervisors, mechanics, and management are and continue to work extended hours to ease the issues as best they can. While the focus might be on missed or late trips, for which NZ Bus apologises, there is little recognition of over 150,000 completed or on time trips."
He said the new network, which went live in July last year, needs time to bed down.
"Full operationalisation of a new network requires time to bed down, with many elements required to operate in harmony, which remains a work in progress for all the public transport partners. NZB and GWRC have been, and continue to work very co-operatively to improve service performance and reliability."
In January 2018, NZ Bus successfully secured five decade-long contracts in Wellington, to a total value of $323 million.
Mr Eagle wants NZ Bus to relinquish those routes and said the council would be able to come up with a solution.
Councillor Daran Ponter said whether NZ Bus would stay or go, was something it would have to decide soon.
"We will have to determine in the next few weeks whether their performance is so inadequate that we have got to that point.
"The difficulty is however ... then what. Because while that sounds good to strip off the services from NZ Bus and allocate them to somebody else, we have to have that somebody else to allocate them to."
Mr Ponter also wanted the amount the company had paid in fines made public - something which currently could not happen due to commercial sensitivity.
He has sought legal advice on whether that figure should be released.
He also said due to the driver shortage NZ Bus had 21 permanent cancelled services a day but was commonly cancelling 20 or 30 more each day at the last minute.
"I have really struggled over the last few months with NZ Bus. Hugely disappointed.
"At its very base level I think that NZ Bus has disrespected Wellington ratepayers and Wellington bus-users. I have got to a point where i have lost confidence and faith."
Wellington-based National list MP Nicola Willis said the government should have stepped in months ago.
"It was clear months ago that these were systemic issues that were not going to be resolved. As early as October I was calling for the government to put in a Crown observer because I could see it wasn't getting better, Wellington bus users could see it wasn't getting better ... here we are."
She said the regional council needed to own the problem, just as much as NZ Bus, and should be helping NZ Bus meet its obligations.
"I don't think it's beyond any provider to put in place incentives that mean people want to work there, they want to drive their buses and they turn up to work - that's about being a good employer and the regional council needs to make sure providers are incentivised to do that."
Ms Willis said the council needed help to rectify things.
"I don't have faith in the council to solve this by itself - it's been promising to fix things since the new system was put in place.
"I think the government needs to send in a Crown observer and use its powers under the Local Government Act to fix these problems."