He said the new institution would maintain equal functions across the two existing campuses in Rotorua and Tauranga.
There were 106 submissions received during the public consultation that were considered alongside the business case and additional information supplied by both councils about the proposal to merge.
The majority of submissions received were negative.
Waiariki council chairman Graeme Nahkies said its first task was to "create a smooth process to transition our staff and students to the new institution".
"The new institution will continue to play an important role in improving participation in vocational and professional education and training."
But Keep Waiariki Local spokesman Tamati Coffey said the lobby group was "really disappointed" the merger was approved.
"While we were pleased the community was able to put our views in front of the minister, unfortunately he has decided to push ahead with the merger - despite a greater number of negative submissions."
New Zealand Union of Students' Association president Rory McCourt said the community had been ignored.
"Minister Joyce has decided to railroad this merger through despite widespread opposition in the community."