Land beside the St John buildings had been leased so the new building could be expanded.
St John Tauranga Building Project Charitable Trust representative Glenn Keaney said they were approached to "get some momentum behind the project".
"It's been two-and-a-half years in the making, fundraising, design, construction, dealing with all the sort of things thrown at us."
TECT chairman Bill Holland said it gave slightly more than $2 million for the project.
"We were a key funder for it and they were able to get some leverage of that," Mr Holland said.
"There has been a lot of fundraising around it, the community has been very supportive because everybody knows and respects what St Johns do. So that's why we were happy to support it."
"It really was a collaborative effort."
The entire project, including planning, design, architects and engineering, construction and landscaping would cost $5.2m.
Donors to the St John project
-TECT
- New Zealand Community Trust (NZCT)
- CIB Charity Luncheon
- Acorn Foundation
- CBC Construction Limited
- Gordon Robert's Charitable Trust
- Tauranga Rotary Club
- Lions Club Zone 9
- The Tauranga Area Committee, Order of St John
Businesses from 247 Cameron Rd building which provided trustees for the project were:-Realty Services
-KPMG
-CooneyLeesMorgan
-Staples Rodway
-Aurecon
-ANZ
-Key Research
-Rothbury Financial Services
-Elizabeth Cafe & Larder