The money also pays for jitney (Filipino public transport) rides to Trinidad, where Mr Royals said the nuns often travelled to help the sick.
Mr Royals also paid for eight new rooms to be built in the convent. Until now, the money has come solely from his own pocket.
But now Mr Royals is appealing for donations from the public for what he called "the big one" - renovating the dilapidated convent.
"This is a big one.
"The Japanese had it in 1943 and it was mucked up a bit but it's stable and secure enough to do something with without pulling it down, so we're going to renovate the front of the building for them."
He hoped to raise NZD$28,000, and would supplement the remaining amount with his own income.
Mr Royals had several thousand leaflets printed with information on how to donate, but the account number printed was incorrect. The correct number is 06-0493-0550624-00
"The nuns do so much over there - and these girls are in their 80s.
"Without the money, they can't do much at all, they get some food but it's a battle," Mr Royals said.
"I've made a huge difference in their lives, I'm very close to all of them now and I've been welcomed into the convent now after all these years - men aren't allowed in there usually.
"So it's very, very special, it doesn't get any better than that."
He said other individuals and organisations also helped the nuns.