The Automobile Association has shared that a substantial change in petrol prices for all those customers who choose to pay for their purchase via credit cards at some BP stations across Wellington would end up driving customers away.

Already, BP staff has been reporting that customers are upset about the extra fee levied, with many opting to go to other gas stations instead, or "swearing and abusing" employees.

According to AA spokesman Mike Noon, the "convenience fee", which 5 independently owned BP stations started charging from Saturday, is bound to increase competition.

"It adds about 3.5 cents a liter on a $30 bill, which I think is quite a lot. For quite a lot of people it's the equivalent of the supermarket docket discount", he said.

All those customers who pay using their credit cards are now charged 60 cents extra for every transaction which is below $30, and 90 cents for every purchase which is over $30.

The gas stations which have confirmed the new charges include Berhampore, Newlands, Ngaio and Karori.