"I think there is a lack of awareness. A lot of these drivers aren't confident drivers. They feel constrained on the normal, two-laned road," he said.
"They're driving safely and cautiously, but without consideration for other road users."
Nationwide, the South Island was the most ticketed part of the country last year, with Southern, Tasman and Canterbury the top three ticketed districts.
Slow drivers were not a risk in themselves, but contributed to risks on the road, national road policing operations manager Inspector Peter McKennie said.
"The risk is around impatient drivers passing when it is not safe to do so," he said.
"Police would also encourage motorists who are driving more slowly than others to find a safe place to pull over and let traffic pass."
It was difficult to know why there were so many tickets issued in the Southern District without close analysis, police said.
However, not all slow drivers were tourists or the often-slated elderly drivers.
"Typically speed eases as you get older but slow and inconsiderate driving is across different ages and groups.
"It's no good for anybody when there's a driver that feels nervous and intimidated and under pressure when they've got a driver tailgating them, and it's no good for the car behind if they then do something rash."