Petrol has dipped below $1.70 a litre in some areas as competition between oil companies heats up.
Photo: RNZ
The discount, which would end at midday today, was kicked off by Gull and matched by Z and Caltex in selected locations.
Gull said customers would pay between $1.659 and $1.809 a litre for regular 91 fuel.
AA's petrol watch spokesperson Mark Stockdale said the promotion was a marketing stunt, but overall, companies were passing on savings from lower commodity prices.
"There's a bit of a lag in terms of when they pass those reductions on, they could be passing those on a little bit sooner perhaps on occasion the reduction could be a little bit larger than it is."