The merger of Aoraki Polytechnic with Christchurch Polytechnic Institute of Technology (CPIT) feels like "a takeover" for Aoraki's South Canterbury staff.

Job losses are likely for some Aoraki staff after the Government confirmed the merger to form a new institute, which will then be "resized".

Staff from both organisations were told on June 23 that from seven options, it was preferred that Aoraki be "legally disestablished", with CPIT becoming the "legal entity" of an organisation under a new name.

There are about 120 staff at Aoraki, and 800 at CPIT. It was said "there could be" job losses since there were "some pressures to become efficient across both organisations". How many jobs could go was yet to be revealed.

Tertiary Education Union (TEU) president Sandra Grey said some staff were in shock, despite knowing the merger was likely.

"There is no doubt for the Aoraki staff, this feels and is a takeover of their institution."

The union's focus was supporting staff through finding out their future employment.

"Our CPIT members are obviously aware of what's going on but for them it feels like business as usual for 2016."

TEU urged caution in rushing decisions through, since a good merger took a couple of years to work through, Grey said.

Staff were given about a month to have their say before councils from the two education providers decided on the best option to recommend to Tertiary Education Minister Steven Joyce.

Joyce announced on Tuesday that the merger would proceed. The new institute would open for business in 2016.

"I ... believe merging the two tertiary education organisations will provide the highest quality tertiary education for learners, for the institutions and for the region," Joyce said.

The new polytechnic would be called CPIT Aoraki until a new name was chosen in 2016. It would operate as a regional entity serving Christchurch, Timaru, Ashburton and Oamaru, he said. The new institution would also cover North Otago to Kaikoura.

Planned "centres of excellence" included primary industries, health, broadcasting, sustainable practice, tourism and trades.

The Timaru campus would be upgraded.

CPIT chairwoman Jenn Bestwick would chair the new organisation, with Aoraki chairwoman Janie Annear becoming deputy.

The council said a "resizing" of the new organisation needed to happen, but the numbers were yet to be determined.

"Most" Aoraki staff were expected be absorbed by the new entity, unless they duplicated roles or their role was no longer required.

CPIT chief executive Kay Giles said "at this stage the CPIT jobs remain". For any duplicates in roles, the Aoraki staff would be given the option to take redundancy or a different role.

She understood her role as chief executive would remain.

Staff were informed of the decision by email "pretty much simultaneously" with the Government announcement.

Giles said she had not come across any negativity, but feelings would be different across both campuses.

"I think people are really excited about the opportunities."

Aoraki chief executive Alex Cabrera confirmed his job had been disestablished.

It was too early to say how staff were feeling and he did not want to speculate about future staffing numbers, he said.

Although he could not guarantee everyone would stay, he said he would be working with staff regarding what they wanted to do.

He believed the announcement marked the beginning of a new institution, rather than the end of another.

"I think it's a very exciting future for the region. The two institutions can deliver a much stronger institution with a greater regional approach."

One of the biggest challenges would be completing what needed to be done in time for the disestablishment of Aoraki on December 31, and the start of the new entity on January 1.

The Government invested $7.9 million in Aoraki in 2015, and $58m into CPIT.

The Tertiary Education Commission (TEC) would likely finalise funding for the new organisation for 2016 in December.

"I expect that the new merged organisation will be a top performer in the New Zealand tertiary education system. I am also confident it will deliver even more effectively on the skill needs of the Canterbury region," Joyce said.

Bestwick said the merger was "fantastic news".

"The new organisation opens the way for implementing new and innovative ways of learning and improving accessibility across the region."

Annear said students and local industries would benefit.

"There are some very exciting plans in the pipeline that we can now progress and make a reality."

Students could enrol at either institute, which would be transferred to the new entity, the council said.

Joyce disagreed the merger would have a negative effect on the South Canterbury community.

The larger institution would allow for resources to be pooled, a focus on Canterbury, including the southern regions, and stronger links within the industry.

Public consultation on the proposed merger drew 30 submissions. Seven were neutral, 10 were in favour and 13 disagreed with the proposal.

Joyce would visit Aoraki's campus on Thursday to look around, meet both institutions' chairs and chief executives, and to see plans of the new institution.