Drive off thefts from petrol stations are up by 24 percent on the same time last year according to just released data from retail crime intelligence company Auror.
It followed a trend seen in other countries, Auror said.
Auror's regional director Kaye Harding said Auckland was being hardest hit. About 500 drivers a month did not pay for their fuel in Auckland, Wellington and Christchurch from January through to April, she said.
"It's pretty rough out there," she said.
There was a spike in March when fuel prices reached their highest levels and then numbers settled down a little last month.
"It's definitely increasing across the board."
Harding was unable to put a figure on how much the stolen fuel had cost companies, adding that a lot of stolen vehicles were being used before offenders fled without paying for their fuel.
The most desirable fuel targeted was 96, while diesel was not going up in terms of the numbers of thefts - even though prices have risen.
She said 37 percent of offenders were first-timers.
While there had been an increase in aggressive behaviour in the retail situation, generally, that had not been so evident at fuel stations, Harding said.
Petrol station staff were being educated on how to make better judgements on which drivers should be allowed to fill up before they pay.
There was also an effort to have better liaison with police.
However, "I don't think there's a silver bullet for it," Harding said.