Environment Canterbury is planning a return to the central city.
ECan has been working out of several temporary locations since its Kilmore St offices were damaged beyond repair in the February 2011 earthquake.
It has reached an agreement with the Christchurch Central Development Unit (CCDU) to rebuild their Christchurch office at 196 - 208 Tuam St, which is inside the southern frame.
The Tuam St land purchase and building is expected to cost $41 million.
This will be funded by the sale of the Kilmore St premises, insurance payments and an expected $3 million additional funding., which will be sourced from the organisation's existing property rent structure.
Preliminary plans have been drawn up for a new building of similar floor area to Kilmore St offices and will have a basement car park to meet the southern frame requirement of reduced visible car parking.
It is expected the building will be finished by December 2015.
Dame Margaret Bazley, chairwoman of ECan, said moving the organisations staff to one central site would be a boost for the staff and help with work efficiency.
''[This] sends out a strong and positive message that Christchurch's recovery is underway, and affirms Environment Canterbury's commitment to the city's rebuild.''
Earthquake Recovery Minister Gerry Brownlee said it was encouraging to see ECan committing to the city's recovery plan.
''As the Christchurch rebuild gathers pace we will see more and more organisations and businesses reconnecting and committing once again to the central city."
ECan had been in Kilmore St since 1990, a year after the regional council was created by government reforms.
- The Press
Have you had a ticket in the last five years?Related story: Canterbury speed camera use rises sharply