KEY POINTS:
St Patrick's Day will be observed tomorrow - three days early - by many Catholics, because of the very early timing of Easter this year.
Tradition dictates no feast days can be held during the church's pre-Easter Holy Week.
So inner city Auckland's St Patrick's Cathedral is among those having its St Patrick's Day mass three days earlier than usual on March 14.
"From a church perspective it makes sense to move a feast day out of Holy Week to maintain Holy Week's solemn status within the church," NZ Catholic managing editor Gavin Abraham said.
It is not the first change arising from the early timing of Easter.
For some in South Auckland, the first day of Lent was observed a day later to avoid a clash with Waitangi Day commemorations.
Bishop Patrick Dunn granted the request from the South Auckland deanery meaning Ash Wednesday - as it is known - became "Ash Thursday" for some.
The rare situation came about because the combination of the early Easter and leap day in February placed the sacred on February 6.
It is widely acknowledged the earliest Easter Sunday can fall is on March 22. This year's March 23 timing means it is the second earliest possible and it was last seen in 1913.
The Waitangi Day move "totally astounded" a contributor to the Catholic online forum beingfrank.co.nz, who said they were "dumbstruck".
"What happens if another Deanery discovers that some other integral liturgical commemoration clashes with another big cultural event, like say the 2011 World Cup final, which will be played at home and is almost certain to feature the All Blacks?"
One Auckland father said it sparked disagreement and Bishop Dunn attracted "a great deal of criticism from around the world" over the issue.
