There is cautious optimism over the government's plan to expand road user charges to petrol vehicle drivers, with one advocate saying the move is a long time coming.
The government hopes to make all petrol vehicle drivers pay the charges as early as 2027, while at the same time phasing out fuel excise duty.
It comes after it passed legislation earlier this year to make electric vehicle drivers pay the charges,
The opposition said the 2027 timeframe did not leave a lot of time for the government to fill in the detail, but advocates said it was a good move, as the current fuel tax system was outdated and unfair.
Road user charges were paid depending on kilometres driven, rather than amount of fuel bought, which would put some on a fairer footing, New Zealand Initiative executive director Oliver Hartwich said.
"People from relatively underprivileged backgrounds, poorer backgrounds, they often drive cars that use a lot more fuel, because they are often driving older cars that are less fuel efficient. So in effect, you're asking them to pay more under the current system, whereas in the future, they might actually pay less."
Hartwich believed the 2027 timeframe the government had planned for was realistic and doable.
The Automobile Association's policy director Martin Glynn was less sure. He said with 78 percent of New Zealand's fleet being petrol-powered, a lot of work would need to be done.
"There's a huge system change. Probably more than an overhaul, a whole new system that'll need to be designed to put the whole fleet on it," he said.
"Bringing three quarters of the fleet, the petrol-powered vehicles, into that is a huge undertaking, in, what, three years' time? We'll have to see, a lot of work to be done."
Replacing fuel excise taxes with electronic road user charging was part of National and ACT's coalition agreement and could lead to changes in the way road user charges are administered and monitored, such as using GPS.
Hartwich said a system that tracked location and driving data would inform good transport policy.
"In the future, we would have much better data. We would have it almost real-time, and that would really help us, help our councils, help [the New Zealand Transport Agency], help the minister of transport make better decisions on where roads are needed, where traffic speeds are low, where any other traffic measures might actually be needed," he said.
"And so I think actually, this additional level of data telling us how we should redesign our transport policy in order to get better results is one of the really appealing features of that system."
He acknowledged there would be privacy concerns, but was confident the government would address those.
"Obviously it's a privacy concern, and it has to be dealt with. Then again, the same people concerned with that should probably look at their mobile phones, because mobile phones are pretty much doing exactly the same," he said.
Glynn suspected the electronic RUC was more of a long-term goal.
"The focus will need to be on the current system and making some adjustments to make it more user-friendly and easy to comply with for users. Doing that transition into the electronic road user charges, where every single vehicle in the country needs a device, that's a much bigger undertaking, so I suspect that's somewhere beyond," he said.
Labour said it was open to considering the merits of all vehicles paying road user charges, but it had some reservations.
Its transport spokesperson Tangi Utikere was concerned at the short lead-in time, and said the way prices would be set needed to be fair and reasonable.
"There needs to be a transition period, there needs to be really good lead-in time. This is not something that can just be rushed. Yes, there is a lot of innovation out there, it's important that innovation is utilised. But it's also important that there are no barriers if we are moving to a RUC system," he said.
"For example, having to pay up-front is a RUC cost, some people will find that a bit of a challenge, so there are lots of things that still need to be worked through."
Green MP Ricardo Menéndez March said the party would be keeping an eye on the rollout, particularly on whether people's privacy was respected.
"It's about time. But it needs to be coupled with greater investment in public transport, to give people more options on how they move around too," he said.
Transport Minister Simeon Brown said the change would ultimately would mean all road users paid for upkeep and maintenance, irrespective of what vehicle they drove.
The government still planned to increase fuel excise and RUC in 2027 - the same year it intended to bring in the change. But Brown said until that transition happened, no motorists would have to pay both.