On Tuesday, Ardern said Kiwis had been "fleeced" at the pump for around a decade.
Her criticism followed a draft Commerce Commission report confirming the fuel industry was not as competitive as it should be - and Kiwis paid too much for petrol.
The Government had already started work on how it could drive down fuel prices, Ardern said.
Hawke's Bay is the second cheapest region in New Zealand to fill up at the pump.
The average price across the region per litre for Unleaded 91 in August 2019 has been $2.05 per litre, a single cent more expensive than Bay of Plenty, petrol price app Gaspy data shows.
The country's five cheapest fuel stations are all located in Bay of Plenty.
Before her Nissan, Marriott owned a Subaru Impreza and the costs were far larger in comparison then to now, she said.
Not only for fuel too, with maintenance costs and the usual warrant of fitness woes making for a strong headache. With her Nissan, however, life was a breeze.
While some electric vehicles were expensive, Marriott said her Nissan, which was second-hand but without much mileage, only cost her $22,000.
Friends of hers were forking out the equivalent for small cars which required fuel to run, which was "mad", Marriott said.
Asked whether she would advise other motorists to get on board with the electric vehicle movement, she said yes, "I'm trying to talk everybody into it."