"We've had it before where we've fitted in 92 comfortably — well, sort of holding your breath comfortably," she said.
Once the church is full, the rest of the congregation will have to stay outside, in marquees behind and at the side of the church with an audio visual system to broadcast the service.
"I'm confident we are going to be able to get everyone in," Nathan said.
Such is the confined nature of the church and its grounds, that cars will have to be parked at Whakaue Marae with people either having to walk to the church or use the shuttle that will run from 8.45am until the 10am start.
One of the highlights of the service will be the unveiling of a glass case containing a Bible that is older than the church itself.
The Bible was given to Maketū's first local Anglican minister, Ihaia Te Ahau, when he finished his training. It is dated April 29 1858.
Rev Te Ahau was the minister in Maketū when work began on building the church, although the driving force behind its construction had been missionary Rev Thomas Chapman, who first dreamed of a church in Maketū 30 years earlier.
An altar cloth that came from England in 1908, and a plaque will also be unveiled at the service.
Among the dignitaries at the service will be The Rt Rev Ngarahu Katene, bishop of the Māori Diocese Pihopatanga Hui Amorangi o Te Manawa o Te Wheke, Archbishop Donald Tamihere, Bishop Andrew Hedge, Reverend Don Rangi (Vicar General Te Upoko o Te Ika) and the Venerable Michael Tamihere.
Retired Bishop George Connor will give the sermon.
"It's not often we get all of the bishops together in one place on one day, but this is a big celebration for Maketū," Nathan said.
Ministers and others who had associations with the church had been invited back and organisers were expecting them all to turn up.
As well as Nathan's ordination as a priest, Vianney Douglas would be ordained deacon and Tuakare Mahutaariki would be commissioned as kaikarakia (prayer leader).
Nathan has been at St Thomas' for five years, first as a lay reader then kaikarakia, becoming a deacon in 2016.
"Prior to that I was at Te Puke Anglican Church," she said.
But she has called Maketū home for 12 years and has affiliations with Ngāti Pikiao, Ngāti Whakaue and Ngāpuhi.
One of the delights of organising the celebrations was the people she had met and the stories she had heard.
"One lady told me about the gifting of the land [for the church] by her great-grandfather," she says.
"People talk about things, open their hearts, talk about their families and their memories and that's a privilege.
"I know it takes them back in time and to see them connect with their past is quite special and it's wonderful to hear the life of St Thomas'.''
There is a service at the church each Sunday morning.
"Normal [congregation] numbers are 26 to 30 but in winter it always dropped off to 10 to 15 people."
St Thomas' Anglican Church 150th anniversary
Saturday August 25 4pm pōwhiri at Whakaue Marae
7pm compline — night service
Sunday August 26 8.45am Shuttle from Whakaue Marae starts
10am Holy communion service
Hākari [feast] at Whakaue Marae following the service
