With Labour's announcement that a 10c/litre regional tax on fuel is just "four or five months" away from being imposed in Auckland, petrol companies are taking a close look at where their stations are situated.
Incoming Transport Minister Phil Twyford told The AM Show the levy is likely to arrive by March 2018, and is anticipated to contribute about $1.5 billion over 10 years towards combatting Auckland's congestion.
Most petrol stations sit comfortably well inside the Auckland zone, and are unlikely to notice any meaningful changes to business. Others, however, sit far closer to the border, putting their competitors just outside Auckland - but still within a few kilometres - at an advantage.
On the Auckland-Northland border, there's not much concern - even though there's a Mobil sitting in Te Hana, about 500 metres inside the border. That's because the closest petrol station in Northland - Mobil Kaiwaka - is still 13.5km away, and is part of the same company.
But on the Auckland-Waikato border down south, things are much more interesting.
BP and Caltex both have petrol stations in Bombay along State Highway 1, 1.5km inside the border - and they're currently hotspots for trucks and other commercial vehicles to fill their tanks.
Just 3km onto the Waikato side of the border sits Gasoline Alley in Pokeno, which is also an off-ramp's-length away from SH1 and is likely to benefit most from the new tax. Its owner Ravi Tiku said he's hopeful it'll boost business at his station.
He thinks a tax of 10 cents per litre is "a little bit over the top" but believes the impact on Aucklanders will be fairly minimal.
"I don't think people in Auckland or daily commuters will worry too much about it - they will just carry on with business as usual," he said.
However Mr Tiku believes people travelling between Auckland and Waikato will now prefer to visit his station instead of the equally accessible stations in nearby Bombay.
"I think there will be [an impact on sales at Gasoline Alley Pokeno], as we're just outside the Auckland regional boundary," he said.
"I'm guessing people coming back from a holiday would fill up before entering Auckland and paying the tax."
He said while Gasoline Alley stations don't have any fuel discount initiatives like those offered at their much larger competitors in Bombay, they will still have the upper hand with drivers travelling between Auckland and Waikato.
BP told Newshub it wouldn't comment on the impact the tax will have on fuel sales at its Bombay franchise as it isn't yet privy to the details. It said it will work with the Govermnent and Auckland Council throughout the process.
A Caltex spokesperson told Newshub: "Obviously there is a still a lot of water to go under the bridge, but at this stage we're not anticipating a big impact on our sites near the Auckland region proposed tax border.
"There will probably be some people who go out of their way to fuel up where they think they might get a cheaper price if the tax is introduced, but most people prefer to shop where it’s most convenient for them, so we’re not expecting much to change from business as usual."