"It's a wonderful, wonderful time for them."
Recently home from working and living overseas in the midst of Covid, O'Neill said as well as being double vaccinated with Pfizer in New Zealand he was double vaccinated again with the Moderna vaccine in London.
"And I'm fine. Vaccines do work. I was living with Covid all around me."
Everyone at this year's opera school is double vaccinated in line with the school's requirement when applying.
O'Neill's name has also been listed in a Grammy nomination, with the awards to be announced in Los Angeles on January 31.
He was solo tenor in the extremely demanding role of Dr Marianus in the Grammy-nominated Mahler's Symphony No.8 under the baton of megastar conductor Gustavo Dudamel and the Los Angeles Philharmonic. It has been nominated for best choral performance and best engineered album (classical).
"It's very exciting but I won't be there sadly. I will be heading back to Europe - that's where my work is. Even though we only have 50 per cent of our audiences [due to Covid restrictions], we are still working in the great opera houses of the world."
And those great opera houses were where many of the young singers would eventually be - and so many already were, he said.
"The absolute beauty of our young singers is that we are multi-cultural and so are producing superb voices. Our opera school is simply their magnificent beginning, a school to be so proud of."