National coordinator Simone Frewin of Northland said in the six weeks the campaign had been planned it had "snowballed" into a major event.
"It just proves what a huge issue this is for riders."
Frewin said horse-riders didn't want the right to regularly ride down Queen St, but "we just want to be safe on the rural roads where we live".
They wanted drivers to understand that passing at 20km/h and giving a horse a 2m berth was crucial.
The Ride for Road Safety campaigners said legislation was ambiguous, stating motorists must "slow down or stop" and give a rider "plenty of room".
"It takes less than a minute of your life to slow down and pass safely - or you can take a life in less than a second if you don't slow down," said Frewin.
In Saturday's biggest ride, 100 riders and walkers will travel Blackbridge Rd in Dairy Flat from 10am - just a few hundred metres from where Curious George, was hit and killed.