Police who deliberately baited motorcyclists to break the law then fined them have been exposed in a recent court case, leading to a magistrate describing the police as ''reckless''.

The finding could pave the way for scores of other riders caught using similar tactics to reclaim demerit points and fines.

The operation featured in the case took place on September 16 and 23 last year in a section of the Old Pacific Highway between Mount White and Brooklyn. The Ku-ring-gai highway patrol issued 68 tickets, all to motorbike riders.

Brothers Rod and James Ward were booked for crossing the road's double dividing lines. They were each fined $298 and lost three points. James said they had been on a casual ride when, ''in a flurry of dust and gravel'', a grey SUV pulled out in front of them, then sped up and slowed down several times. ''People were moving around inside the vehicle and there was a commotion going on in there and we didn't really know what was going on,'' he said. ''I thought initially it was some tourists who had been lost.''