The American transport consultant behind Wellington's new bus network blames the capital's bus chaos on the implementation not the design.

Photo: RNZ / Emma Hatton

In July, Wairarapa bus company Transit took over the contract for half of Wellington city's bus routes, which was also when the city's bus routes changed.

Since then, commuters have vented frustrations about overloaded buses and buses not stopping because they were too full.

Consultant Jarrett Walker told RNZ the system does work but Wellington's implementation was flawed and caused the problems passengers faced.

"It does work, however, there are many, many things that can go wrong and it sounds like some of them are going wrong in Wellington," Mr Walker said.

"If I were in Wellington living through this right now I'm sure I would be as furious as many as the customers are."

The sign-up of a new bus operator only added to the problems from the execution of the new plans, Mr Walker said.

"All sorts of things have gone wrong at the same time, which is why you can't really judge the network design based on the unfortunate things that are happening around the implementation."

However, Greater Wellington Regional Council chairman Chris Laidlaw last month said the council wouldn't have done anything differently in its implementation of the city's new bus services.

"The process was correct. There were some unique things that we had to deal with, one of them was a driver shortage, one of them was a large change in tender provision that was not a natural outcome but what the process drove," Mr Laidlaw said.

"It gave us a combination of events to manage with and we've just managed them as best we can."

Since the changes, bus passengers have also frequently complained about "hubbing" - which requires users to make multiple bus changes to complete their journey.

Mr Walker said he last worked on the network plans six years ago, and it was the original hubbing scheme that he defended.

"I can tell you how it should work is that connections should be fast, they should be timed so that you wait only a few minutes at a connection point, and that's certainly what we intended when we designed the network.

However, he did acknowledge that not everyone would view the hubbing model as an improvement from the old network.

Wellington's constrained paths and original bus problems were what triggered the development of the new system, he said.

"We make an argument about where this needs to be done... in that particular geography it made sense that we could not run a direct bus service from everywhere from every bus stop in the city."

The council said it was looking at a review over the next eight weeks to figure out what could be done to manage passengers' concerns and fix parts of the network that were not working for commuters.