Rather than having one priest based in Masterton, one in Featherston and a visiting priest on weekends, it was likely two Masterton-based priests would be appointed to serve the new parish, Mr Wagg said.
The appointments would be made public shortly but it was likely the number of weekend services across the new parish would be reduced, he said.
"There won't be the same level of daily services."
"The two priests will be spread over the two regions so there won't be the same level of activity."
However the chairwoman of the working group implementing the changes, Marilyn Bouzaid, said the number of priests and services under the new parish was yet to be confirmed.
With priest numbers declining it made sense to centralise, Miss Bouzaid said.
"It's just more sensible, possibly, to centralise finances and administration - particularly in the electronic age."
Carterton parish lay pastoral leader Sharon Penny said it was a chance to revitalise the Catholic church in Wairarapa.
"It's quite an exciting change for the church. It gives us a chance to look at ourselves ... what we are doing and what we want to keep.
"It's a new way forward really."
Some parishioners were concerned by the centralisation while others saw it as an opportunity, she said.
"Like any big organisation, when it gets bigger, people wonder if their voice will get lost. [But] for a few there was a sense of excitement."
A plan outlining how the changes would be implemented had been submitted and accepted by the Archdiocese, she said.
It was expected the plan would be used as a "living document" and might be subject to further changes following consultation.
It was important the new parish was inclusive, Mrs Penny said.
"It's making sure we respect each community because communities form bonds and that's where people gain confidence and support - in their own community."
Mrs Penny will retain her position as lay pastoral leader under the new parish.
According to the 2013 Census, 4224 people in Wairarapa identify as Catholic.
The new parish inaugural Mass will be held at the Masterton Town Hall on March 1, with the Archbishop officiating.
People wishing to discuss the changes can attend a public meeting at the Carterton Events Centre on November 30 at 2pm.