Residents who border the park were horrified to learn of the event
The organiser, who wished only to be known as Dane, said he was hoping for a turnout of about 100 people.
"This is an R18 event and everyone over 18 is welcome," he said. "J Day is not about breaking the law, but people showing their support for sensible cannabis laws.
"Polls show more than 80 per cent of New Zealanders support making cannabis a health issue, not a crime, and safe legal access to medicinal cannabis. Many others agree that the best way to prevent synthetics coming back is to allow real natural cannabis."
One horrified resident who lives next to the park but did not wished to be named, said: "I had no idea this was happening. I have a teenage daughter and run a business from my home and definitely don't think this is an appropriate place to hold an event like this.
"This can't be an R18 event as this is a public park and is one of only two parks where people are allowed to walk their dogs. It's also well used by lots of young families."
Parkvale resident Vallanne Onslow-Barlett, 69, who walks her dogs in the park twice a day, said: "I don't think it's an appropriate place to hold this sort of rally, and I certainly will be staying away as I wouldn't want my dogs or myself to ingest any cannabis.
"There is likely to be lots of families with young children using the park, people having barbecues and sometimes there are weddings going on in the park."
Greerton mother Estefania Babuglia, 35, said she and her 10-month-old daughter used the park every day.
"I'm originally from Uruguay where using cannabis is legal but before it became legal similar events like this were common, but I'm not sure a public park is the appropriate place to light up."
Ms Babuglia said maybe it was time for New Zealand to review its cannabis laws as alcohol and cigarettes were "probably" far more harmful than cannabis.
Aotearoa Legalise Cannabis Party leader Julian Crawford said J Day was aimed at showing the general public that cannabis users were "just normal people" who came from all walks of life.
Mr Crawford said a lot of countries had relaxed their cannabis laws with good results and New Zealand needed to follow suit.
"Here in New Zealand people caught using cannabis continue to be treated like criminals. Criminal convictions have terrible implications for those people. While some judges do show more leniency, too many people are still going to jail."
The Bay of Plenty Times Weekend sought comment from police.
In a written statement a police spokesperson said they would be "monitoring" this public event to ensure public order was maintained.
