Nabbed... as quick as a flash and a flash

An Auckland motorist was stunned to open his mail and find a speed camera had pinged him twice for the same offence.

Remuera man Tom Piggin was caught over the 50km/h speed limit on Great South Rd on December 10 but has been issued two separate tickets, both recorded at 12:43pm, with the fines citing his speed at 56km/h and 55km/h.

Mr Piggin said he would normally have paid the fines without challenge, but was baffled by the double-up, certain that he had made only one trip down Great South Rd on that day.

"The notices arrived in separate envelopes but on the same day," Mr Piggin told the Weekend Herald.

"Having got two in one hit I thought it was unusual, particularly with the times being the same and only driving the road once."

In response, police admit they got it wrong, conceding it is possible for people to be "very occasionally" fined twice for the same offence.

Police weren't able to provide any statistics to explain how often the errors happen.

The good news for Mr Piggin is that he will have to pay only one of the $30 fines. Police agreed to scrap the second ticket.

"These duplicates aren't specifically counted, so we don't have a numerical figure," said Mark Stables, manager of police's infringement bureau.

"Thank you for bringing this to our attention. These tickets relate to the same set of circumstances and we will contact the driver to advise that only the first ticket (56 km/h) is valid and the second one (55 km/h) will be withdrawn.

"This situation happens very occasionally, when a camera captures an image with the car in the middle of the frame, and again as the car nears the edge of the frame," he said.

"In this case, the car had slowed by 1km/h when the second photo was triggered. Our staff would normally pick this up and not issue the second notice."