"It's not that usual [to switch denominations] but I suppose more in common is my theology - what I believe in [about] God fits very comfortably with St Lukes people.
"It's a place that understands compassion to guide doctrine, rather than doctrine to guide compassion."
Asked if the issue of performing gay and lesbian weddings weighed in his decision to leave, Rev Cardy said it hadn't.
"St Mathew's has taken a lead in trying to promote gay marriage in the Anglican church and I think that eventually that might change.
"That might take many years, but that's not the reason I'm leaving. I've got good relationships with the bishops of Auckland and there's quite a lot of sadness about leaving the Anglican church."
He hasn't always been on the right side of his superiors. In 2009 the incoming Bishop for Auckland Ross Bay said in an email that the vicar would not be archdeacon of Auckland much longer.
Rev Cardy said social activism was a strong part of who he was as a person. He was worried, for example, about the proposed Auckland Council beggar bylaw and the poverty that makes begging necessary for some.
"I believe that faith isn't just for people who are believers. It's about a way to promote compassion in society as a whole. There's a message there about how to treat one another and how to be just in society."
Auckland University School of Theology head Dr Stephen Garner said there were few issues with Anglican, Methodist or Presbyterian ministers moving between denominations.
There were agreements in place for that to occur, although Rev Cardy would have to apply to the relevant regional presbytery first. He would still remain an ordained Anglican priest even when he moved to St Lukes, Dr Garner said.