Continuing earthquakes are pushing some Christchurch people to breaking point, with children regressing to behaviours such as bed-wetting.

One Christchurch psychologist says the disruption to daily life resulting from the quake damage seems to be taking a greater toll than the aftershocks themselves.

The aftershocks have kept coming since the February 22 quake in the city that left 181 people dead. On Monday - only a few days after scientists revealed there was a one in four chance of another big quake in the year ahead - the city was rattled by a frightening 5.5 magnitude aftershock.

Lucia Miles lives in the eastern Christchurch suburb of Linwood with her husband and five children, and says the fear of another quake is always in the back of her mind.

"It's like sitting on the edge ... and waiting for it happen," Mrs Miles said.

"You know it's going to happen but you don't know when. Every time you have these shudders, you don't know how big it is going to get."

"I quite believe there is going to be another [large quake], and it may even be bigger than the ones we have had."

Clinical psychologist Fran Vertue said there was considerable stress among people in Christchurch.

"But it's my belief that it's less directly linked to aftershocks than to the ongoing difficulties with getting on with your life. I think that's what's stressing people out and wearing them down."

Child and adolescent psychotherapist Mandy Maoate, who has worked with children affected by the quakes, said she had seen regressed behaviours such as bed-wetting, fear of being separated from parents and nightmares and sleep disturbance.

Some children had grown used to the shaking, but others were "re-traumatised" with every new quake. The effect on some fitted the criteria of post-traumatic stress disorder, Mrs Maoate said.

At home with the children while her husband is at work, Mrs Miles' greatest fears are for her five children living with her, aged 19 months to 10 years old.

"I won't let my daughter play in the conservatory because I'm worried about what might happen to her. My son screams hysterically when we have the quakes."

Mrs Miles said her family were tied to Christchurch because they owned their quake-damaged home, but if they were renting they "would just go".