He has long been a celebrated son of Hamilton, where a Riff Raff statue stands and where a fundraising concert will be put on by Mr O'Brien in March 2012.
There was controversy surrounding Mr O'Brien's citizenship last year when an application was declined because he did not fit immigration criteria.
There was a public outcry from fans, some of whom set up Facebook pages "Let Richard O'Brien be a New Zealand Citizen". Immigration officials then announced they would waive the usual requirement for people to have had residency for five years before applying for citizenship.
Mr O'Brien will now take part in a citizenship ceremony on December 14.
"I feel it's right. I got to England in 1964 and I was a New Zealander, a Kiwi. I loved it, I've always loved the country," Mr O'Brien said.
"I'm standing here looking out the window and on one side you have rural New Zealand, looking towards the Mount and on the other side is a beautiful valley."
Mr O'Brien shot to fame when he wrote and starred in Rocky Horror but is also well known as a writer, actor, television presenter and theatre performer.
He said he had ensured his children had close ties to their aunts and uncles, who also live in Tauranga, and when he was based in the UK.
He would let no more than three years go by without a visit to New Zealand.
After years of splitting himself between New Zealand and the United Kingdom, he is almost settled now. "I want to make sure I live here more than I live there," Mr O'Brien said.