Dunedin man Darryl Smith was sexually abused as a child at institutions in both New Zealand and Australia, including Marylands School in Christchurch.
Marylands was run by the Hospitaller Order of the Brothers of St John of God, one of the oldest orders of the Catholic Church.
Mr Smith first visited Rome in 2019, with the intention of meeting Pope Francis, but was denied entry to the Vatican.
Cardinal John Dew, of Wellington, also declined to meet him, despite Mr Smith being the only New Zealand survivor in Rome at the time.
Mr Smith was dismayed by the outcome of his first trip and hoped this time his concerns would be heard.
"By the time I went there the first time, I had high hopes that the Vatican would actually do something for New Zealand and it did nothing.
"They’ve been all talk."
On Tuesday, Mr Smith departed from Auckland Airport on his second journey to Rome.
He would take four copies of a royal commission interim report, "Stolen Lives, Marked Souls", to be distributed to the brothers’ head office in the Vatican and tabled at an international survivors meeting, which began yesterday.
Mr Smith also planned to meet and demand accountability from Brs Joseph Smith and Brian O’Donnell, two church provincials who were at the head of the order at the time of his abuse in the 1970s and ’80s.
The Catholic Church had no honour and was "worse than any criminal" in the country, he said.
"I’m nearly 60 and I won’t stop until I get what I want.
"I want justice, not only for myself — we’re talking about real justice."
While he said he had the support of both the royal commission and the New Zealand government, Mr Smith funded the trip himself and from donations.
Within 22 days, he had raised all the money he needed on his Givealittle page.
"It’s pretty big for me to actually do all this stuff, but I have to do it.
"I have to make sure they’re held accountable," Mr Smith said.
Network of Survivors in Faith-based Institutions and their Supporters spokesman Dr Murray Heasley, who would also be attending the meeting in Rome, said the trip was a testament to Mr Smith’s endurance.
"He’s been relentless in his quest for justice," Dr Heasley said.
Ending Clergy Abuse Global (ECAG), which had organised the meeting, would attempt to pressure Pope Francis to alter canon law so no offenders could have access to children, he said.
Mr Smith was among more than 100 survivors representing 21 countries and one of the few who were self-funded, Dr Heasley said.