The tweet has since been taken down but a spokeswoman for Destiny Church said Tamaki had been invited to speak at the traditional worship event at Te Tii.
She said around 2000 supporters and riders were expected to be there.
The riders include patched gang members but the spokeswoman said they would not wear their patches on to the marae.
Reuben Taipari, who has organised the forum tent at Te Tii, where speakers including Don Brash will appear this year, said he had invited Tamaki to speak there but the invitation had been declined.
"Now that the forum's full, of course, I think he regrets that he's not participating. So his idea is to call up his own facility and attract all the attention over there. And I'm sure that he'll get some. So good luck to him.
"His plan was to have his own event so that's what he's doing."
Taipari said the presence of 2000 supporters, including a motorcycle club and patched gang members was fine, "as long as they are respectful in the event that they're holding I've got no problem with it".
Kitohi said he understood Tamaki was taking part in a larger event organised by some locals.
Government Minister Shane Jones would be giving the sermon at the Anglican event, he said.
Tamaki and Destiny Church have lobbied the Government for some time to allow its ManUp programme to operate inside prisons, saying it worked for Māori where other programmes failed but all their funding applications had been turned down.
At a recent event at Parliament Tamaki presented Justice Minister Andrew Little with a petition urging the Government to allow the programme in prisons.
Tamaki has also said he has lodged a claim with the Waitangi Tribunal that Destiny Church was being discriminated against.
