North Shore doctor and cycling fanatic Alastair Borwick says most cyclists have stories of close shaves with motorists who drive close to deliberately give them "a bit of a fright".
Once Dr Borwick and some cycling mates were nearly hit by a driver in West Auckland. The group chased the man to shops in Titirangi and very nearly ended up in a punch-up.
"It was entertaining for the people over the road in the cafe. We got the police there and they got a bit of a talking to and that was it," said Dr Borwick.
But he said dangerous attitudes from motorists could sometimes have tragic consequences, such as the hit-and-run incident that killed cyclist Dr Graham Robinson near Helensville on October 14.
"It happens every week a car will go past and swerve towards you.
"I'm sure they go, 'Oh well, I will give this guy a fright', and probably with Dr Robinson that's what he [the killer] did and he misjudged it. Obviously you can't do that - the results are totally tragic but it happens a lot," said Dr Borwick.
The 50-year-old is one of 1500 cyclists competing in today's gruelling 192km K2 race which snakes its way around the Coromandel Peninsula from Whitianga.
Now in its eighth year, the event comprises four continuous stages and has attracted quality fields in the past, including Olympic gold medallist Sarah Ulmer and former world junior road-race champion Jeremy Yates, who is back to defend his title this year.
Dr Borwick, who has completed the K4 - where cyclists have to complete the K2 circuit twice - and a 315km non-stop double lap of Lake Taupo, said he preferred endurance races.
He thinks the longer rides are "easy".
"Some people have said I am crazy but it's simply a matter of management. The longer races are much easier to do than one lap flat out."
Roadcraft K2 co-race director Andy Reid said the race was considered by many as the toughest one-day race in New Zealand.
Waikato road policing manager Leo Tooman is calling for patience from motorists after an incident in last year's K2 when a ute overtook a big pack of riders but cut them off to avoid collision with an oncoming milk tanker.
A large pile-up of cyclists resulted and a 43-year-old Auckland man was taken to hospital with spinal and head injuries.
"What we're asking is that should you encounter these lead vehicles heading towards you, pull over until the peloton has passed," said Mr Tooman.
Meanwhile, Orewa Detective Mark Palma said inquiries were continuing into the hit-and-run death of Dr Robinson on Peak Rd.
Police are checking the Transport Agency's vehicle registry for owners of a white or cream Toyota Hi-lux ute, probably a 1980s or 1990s model.
Anyone with information on the white ute or the crash is asked to call police on 0508 PEAK RD (0508 732-573).