After the first break-in, Te Timatanga Ararau trust member Heather Skipworth, who manages Iron Maori Gym, invited whoever was responsible to return, take up a membership and turn their life around.
Instead she was met with more of the same.
Another trustee, Lee Grace, said the window that was shattered after it had a brick thrown through it this time was the one right next to the one that was broken last time.
After posting photos of the break-in on a public Facebook page, there has been an outcry of support from fellow gym-goers.
One post said: "Seriously? That's pathetic. So sorry to hear this has happened, not once but now twice! Not on ... come on people, have some respect!"
And another: "That's awful, a beautiful thing like this to offer a community in which to enhance it, destroyed. Very sad. Sadly it would appear cameras maybe your only option."
Mr Grace said since the last break-in the gym instructors were now putting the gear away to make anyone's job who may try to break in harder.
"We extended the invitation to come back and they might have come back, but not in the manner that we wanted," Mr Grace said.
While it was disappointing that the gym had been broken into again, it had come as a timely reminder, he said.
New gear was arriving next week, and Mr Grace said they were planning to step up security and take up a kind offer from a member of the community who offered to help.
Security arrived at the gym within six minutes of the silent alarm being activated after the first break-in but the offenders had already scarpered.
Mr Grace said he had no inkling as to who might be responsible for either break-in.
He said he had heard a car was also broken into that night and the car parking area next to the gym was now being locked for added security.
Police said they had no further information on the incident.