Petrol is down 3 cents a litre, while diesel has been cut by 2c a litre, by market leaders BP and Z (formerly Shell).
BP said it was the company's second cut, following a drop last week as refined petrol product has fallen in the last week while the New Zealand dollar remained strong.
Petrol is now down to $2.14.9 cents a litre for 91 unleaded at most BP stations, with diesel at $1.55.9c a litre. Shell also cut petrol 3c and diesel by 2c today.
BP managing director Matt Elliott said: "The market remains largely unpredictable, as demonstrated by the fluctuations we've experienced this year, but we're committed to passing on the benefits when we can and as quickly as we can."
Last month the four main petrol companies raised the price of regular petrol to $2.229, an all time high.