They were closely monitored by police, but no arrests were made on the day.
However, Gray said on Saturday the health risk was unnecessary and unacceptable.
"Today, a 36-year-old man has been arrested and charged with Failing to Comply with Order (COVID-19) in relation to attending a gathering.
"This man is scheduled to appear in the Auckland District Court on Tuesday, 2 November where he will face a total of three counts of Failing to Comply with Order (COVID-19) relating to previous events."
Today, the Freedom and Rights Coalition released a statement confirming the arrested man was their MC for the day. They also confirmed another man will also appear in court tomorrow.
"He has now been released from custody and both he and one other male will appear in court before a judge tomorrow."
They criticised how hundreds of people congregated at a speedway in Nelson yesterday breaking Covid-19 restrictions, "but the police don't bat an eyelid".
"Instead, they are more interested in charging those at the Nelson protest we hosted."
Gray said the enforcement phase remained ongoing and he wouldn't rule out further charges.
"Police reiterate our disappointment in the actions of the organisers of this event, who went ahead despite police warning them that the gathering was a breach of the current restrictions."
Most were not wearing masks and were tightly bunched.
It was the third freedom protest at Auckland Domain in six weeks.
Police supervised the rally in strong numbers as speakers took the stage.
The 90-minute gathering at the Domain was noisy but free of any major incidents. Rally participants sang the national anthem and a range of speakers addressed the crowd. At 12.30pm, protesters began their march.
Destiny Church founder Brian Tamaki was not present, after being twice arrested over the two previous protests, but his wife was.
Hannah Tamaki took to the protest stage, saying she is a mother, grandmother and great-grandmother and her children, grandchildren and great-grandchildren were with her.
She said residents in Auckland were being held prisoner and she does not care if people are vaccinated or not. People should have the freedom of choice.
She said she'd had a gutsful of manipulation and being prevented from seeing her other children and mokopuna. "I stand here today unafraid and unashamed."