The New Zealand Aria competition convener Ian Edward said Mr O'Neill had recently returned from television work in Rome.
"He is a true international class tenor."
The two judges, who Mr Edward described as international quality judges, were Glenn Winslade and Luise Napier.
"They are based out of Sydney, they work globally and are vastly experienced."
He said he had been sitting with the judges over the three evenings of competitions and said they were truly impressed with the standard of the finalists in all categories.
"This is a credit not only to the singers but to the teachers. The number of overseas entrants show that this is a competition that is known across the world."
Mrs La Grouw said the winner of the open category would take home a prize pack worth $20,000.
This is made up of $10,000 cash, $5000 towards audition or competition fees and $5000 to enter the Sydney Aria competition held in June each year.
This year the full Auckland Philharmonia Orchestra would be backing the finalists with New Zealand born Hamish McKeich as conductor.
Mrs La Grouw said each finalist chose their own aria to sing, but it had to be one within the Auckland Philharmonia Orchestra's library, which could limit their choice a little bit.
Mr Edward said Rotorua was the ideal community to hold such an prestigious event.
"It's got the culture, the infrastructure and first class amenities at the Sir Howard Morrison with proximity to Auckland, Wellington and Sydney."
Results to come.
