Police are reviewing security in the Rotorua Marathon after an angry motorist forced runners into oncoming traffic.
It is the first year the marathon has been held without a police escort. Instead, organisers relied on cyclists in high-visibility vests to lead the race.
But a verbal altercation led to an angry motorist pulling on to the race course last week.
Race winner Phil Costley said he had to run into oncoming traffic to avoid the car while the driver was arguing with official race cyclists.
"The scary part of it was I made the decision to run around the car on to the road and as I did it I didn't know if he was going to pull out," Costley said.