Supermarkets in Auckland are offering customers the chance to save on petrol, but you'll have to be quick to make the most of the deals.

Countdown has put up a huge offer for cheaper petrol this weekend - and competitor supermarkets have jumped on the bandwagon too.

The supermarket chain sent out a promotional email to customers this afternoon about a 45c per litre discount on fuel when you spend $200 at any of its Auckland stores.

The promotion starts at 1pm today and runs until midnight tomorrow. The discount applies to a maximum of 50L of fuel.

PAK'n'SAVE stores in the Auckland area are also offering customers 45 cents off fuel with a $200 spend.

Meanwhile, New World, which is also owned by PAK'n'SAVE owners Foodstuffs, is offering customers a 35 cent per litre discount by spending $150 instore.

The offer is available instore until midnight on Sunday.

The deals are rolling in as Auckland motorists make the most of cheaper fuel, ahead of the introduction of the regional fuel levy tomorrow.

Cars are lining up outside a West Auckland petrol station to snap up what looks to be the cheapest petrol in town ahead of the fuel-tax hike.

The Titirangi Gull petrol station, on 423 Titirangi Rd, is getting a whole lot of business today; with a line of cars snaking down the road.

Its Regular 91 costs $1.99 and its diesel $1.28 today.

According to the popular cheap-fuel-finding app Gaspy, it is the cheapest around the city at this stage.

The Mobil service station on Sandringham Rd was also doing good business, with a long line forming at the pumps just after 1pm.

A worker at the station told the Herald they had started to see more people in the last couple of hours.

"It's not too bad at the moment, but we do have a continuous long line.''

He said they were expecting it to get even busier later today.

The price of Regular 91 at their station was at $2.09 today, he said.

Petrol stations around the city are expected to see a surge of customers today as Auckland Council's regional fuel tax of 11.5 cents a litre starts at midnight.

Money raised from the levy will go towards funding a range of transport infrastructure in the Auckland region.

Some stations around town reported a steady flow of cars coming through and it being a slightly busier Saturday than normal.

Others said they expected a surge in cars later this afternoon heading into the evening.

The Gull on Roscommon Rd, in Wiri, had a $2.087 price tag on its Regular 91 this morning.

A staffer said: "It's not too busy. It's a bit cold at the moment so we might start seeing more people this afternoon.''

The Mobil on Great South Rd, in Manurewa, said before 11am that they were "very busy'' while the Mobil in Ōtara reported a quiet morning at the pumps.

Meanwhile, at the Gull station in Swanson, in West Auckland, a worker said its speed lane was getting really busy and people were queuing up for the slight discount.

The prices going at that station included $2.12 for Regular 91 and $2.07 via the speed card-only lane.

The Pak'nSave on Lincoln Rd, in Henderson, had a price of $2.09 on Regular 91 today - slightly more expensive than the $2.06 at the BP in Birkenhead, North Shore.

And if you are in and around downtown Auckland, you will be faced with some of the city's most if not the most expensive prices for gas.

At the BP on Fanshawe St, Regular 91 was priced at $2.18.

A staff member there said it was a quiet Saturday.

"Maybe later [it will get busier]. We are in the city and so most of the customers are office workers.''

Three ways to get more bang for your buck at the pump:
Shop around: Do the research to check out who has the cheapest fuel in your area. The AA recommends using apps like Gaspy to do the scouting for you.

Take advantage of loyalty discounts: Various outlets offer savings or rewards when you spend over a specific amount, or fill up on a certain day.

Drive to conserve fuel: Accelerate and brake gently and use air conditioning sparingly in order to use fuel more efficiently. Reducing the amount of excess gear in your car can also go a long way.

Source: The Automobile Association