How far should you go for the best deal on fuel?

With the price of a full tank for even a modest car hovering around $200 motorists are looking for the best value at the pump.

Currently fuel prices vary by as much as 35 cents per litre but finding the most affordable gas could involve a drive out of your way.

On a blustery day in Petone - near Wellington - a steady stream of motorists were filling up at one of the better priced petrol outlets in the city.

RNZ asked drivers how far they were prepared to go for the best deal on gas.

"I drive past an expensive station. There's no science behind it probably, just a vibe," said Elisa Ryan.

But Andrew Crawford said travelling out of his way for the right price was "just a waste of fuel".

Kayla Williams said she was on the lookout for the best prices but used her "gut" to determine whether an outlet was too far away to make the savings worth the trip.

"It's it going to be worth me driving that 10km or is it going to cost the same if I go somewhere closer?" Williams said.

Jane Yeadon said she would make the trip to a cheaper outlet but tried to line up a few errands or shopping nearby.

"I looked in my local suburb this morning, it's 30 cents more expensive, so it's easy to find a few things to buy at Pak'nSave and then pop over here and get your diesel," Yeadon said.

"I have all of the loyalty cards and the apps so, no matter where I'm going, I'm always using that," said another.

Consumer's Jon Duffy said recent consumer sentiment research showed nearly half of people viewed fuel as a key financial pressure - a 32% percent increase since July.

But he said discount vouchers and loyalty cards did not necessarily guarantee the best price overall.

Duffy said he was recently tempted to use a 6 cent per litre discount offered by a North Island supermarket until he spotted a self-service outlet nearby.

A quick calculation revealed the station's advertised price to be 19 cents per litre cheaper than the discounted rate from the supermarket's fuel service.

"If I'd not been lucky to have those two petrol stations in close proximity to each other, I might have thought I was getting a great deal with a discount that I'd been offered but actually would've ended up paying over the odds.

"20 odd cents a litre difference in price that's material for many families. It really does pay to shop around," Duffy said.

He said discount suppliers were often relying on cheaper rents and minimal staffing at outlets a little further out of the way.

But the AA's Terry Collins said travelling too far could negate any potential discount.

He said the best bargains were to be had when the cheapest prices were a part of the journey - not the sole reason for covering the distance.

"There are a number of factors that would want to consider. One is the cost of fuel. Two is the fuel consumption of your vehicle, how much would it use to get there? The final one is how much fuel am I putting in the car?

"If you're going to travel all that distance and you're only going to put $20 in mightn't be worthwhile. If you're sitting on an empty tank, the distance is not too far and the savings are big, that's your trifecta," Collins said.

Collins said, even when the best prices weren't close by, there was plenty drivers could do to make sure they got the most out of their fuel.

He recommended removing any unnecessary luggage, making sure tire pressures were up to spec and keeping speeds as smooth and consistent as possible.

"I'll be driving over the Remutaka [Hill Road] tomorrow and I will see plenty of vehicles braking going up the hill. They drive up to the corner really quickly, put your foot on the brake, get around the corner, accelerate again.

"That driving will do about 10 - 15 percent of your gas. Just by being aggressive in your driving style and actually achieving nothing," Collins said.

Collins said - for all motorist's efforts to find the best value gas prices - their foot on the accelerator remained the best way to save money.