Post-traumatic stress from the Canterbury earthquakes may only now be taking effect, and having an impact at work.
A University of Canterbury business expert Tony Mortensen said international research showed stress from major events can take two years to materialise.
The aftermath of the 2010 and 2011 quakes were still a major part of Cantabrians' daily life, and adding to daily stress for workers, he said.
"We have identified a growing feeling among many managers that this behavioural trend is definitely emerging."
Mr Mortensen, the director of UC's Master of Business Administration programme, has been researching how employees in Christchurch are coping.
He said many organisations were seeing an increase in behaviour from petty arguments to more serious incidents.
"Discussions with a number of human resource managers and business owners across Canterbury have indicated that even the most traditionally tolerant employee is starting to show signs of pressure.
"The problem organisations now face is that, whether the stress is work related or personal, the impact on the daily operations is no different."
Mr Mortensen said employers needed to show understanding, without accepting bad behaviour.
Christchurch people needed to remember that the recovery stage was not solely about the rebuild of physical buildings, but also about the spirit of the people.
"The emotional strain on people must be carefully considered if our local businesses are to be successful and achieve their potential in this next stage of the recovery," he said.
"The recently quoted $40 billion spend over the next 10 years provides an unprecedented opportunity to most businesses. However, the real challenge will be keeping staff motivated and focused so that we can all benefit."
Council of Trade Unions spokesman for earthquake recovery and rebuild Paul Watson said it was no surprise that stress levels were high among Canterbury workers.
Overseas experience had shown it could take two to three years for the psychological impact to take effect, and there were significant ongoing stresses for residents.
These included dealing with insurance companies, EQC and other agencies, facing long waits for homes to be fixed or finding new accommodation, and changes to Christchurch schools.
Mr Watson said while employers were very responsive in the immediate aftermath of the earthquake, many were now more focused on recovery.
"It's more the economic imperative coming forward, rather than the empathy that was there post-earthquake."
He said there needed to be a balance between getting on with business and allowing for the needs of workers.
"They also need to keep a watchful eye on them. If they're not in tune with what the employees are suffering, then they're not going to be fully appreciative of the need for flexibility to enable staff time off to deal with all the issues that are going on."