The author of a new report into the proposed congestion charges says the current state of public transport in Auckland is not good enough to implement the scheme outside the central business district.
According to the Helen Clark Foundation and WSP in New Zealand, the Government is expected to announce it will implement congestion charging as part of the final Emissions Reduction Plan (ERP).
A report from the two groups, released on Tuesday, looks at how congestion charging can be implemented fairly in New Zealand.
The author of the report is Tom James, a WSP fellow who was previously a press secretary and acting advisor to Transport Minister Michael Wood.
He told AM on Tuesday congestion charges wouldn't be recommended for an area if it doesn't have sufficient public transport links.
"We know that those on the lowest income spend proportionately a lot more on public transport - up to 28 percent of their income compared to eight percent of those on the highest income," James told AM co-host Melissa Chan-Green.
"So what we said was there need to be sufficient public transport alternatives as well as good walking and cycling lanes in any given area before we recommend a congestion charge in the area to make sure people have the choice whether or not they have to pay."
The only area the report recommends has congestion charges is the Auckland CBD.
"So at the moment, that is the only area [Auckland CBD] we are recommending it for. There needs to be more work to strengthen our public transport to make it more affordable before we recommend it outside the Auckland CBD," James told AM.
If the scheme is implemented by the Government, Wood said it would significantly reduce traffic on the roads.
"Having a look at the modelling being done, in Auckland officials think you will get a traffic reduction of up to 12 percent, which is the equivalent of school holiday traffic all the time," he said.
"So it does have significant congestion benefits and because it's reducing traffic it also helps to reduce emissions."
Eight cities around the world are using congestion charging and the report says fees range from about $0.5 to $8, with London being an outlier at $20.
Wood said officials are currently looking at a peak period charge of $3.50 and an off-peak fee of about $1.75.
He added that people who continue to use their vehicles in a congestion charge zone would get the benefits of reduced traffic, which means more efficient and reliable trips.
The reason why the Auckland CBD was recommended for congestion charges is that data shows it has good public transport options, James said.
"Over half of the people commuting from the North Shore and from the CBD itself either walk or cycle or take public transport," he said.
"So that indicates that there are already good alternatives available so people can choose not to take the charge or not. So at the moment, that is why we are only recommending the Auckland CBD a congestion charge, other areas need to have better public transport links and more affordable transport links before we would recommend it."
Watch the full interview with Tom James above.