The reduction in the Christchurch suicide rate after the city's deadly February earthquake has been attributed to people's increased senseof "community cohesion" from the disaster.
Chief coroner Judge Neil MacLean yesterday issued provisional statistics showing that the number of suicides nationally increased slightly to 558 in the 12 months to the end of June, from 541 in 2009/10.
But in Christchurch, the month-by-month tally declined from six to eight suicides from June last year to January, to just one in February.
Then from March to July there were between two and five suicides a month, a gradually increasing trend that suggests that the city may be returning to its pre-February rate of around six.
Psychiatric epidemiologist Professor David Fergusson, of Otago University at Christchurch, said there was some evidence that an area's suicide rate either remained stable or temporarily declined after a natural disaster.
"This may be due to greater community cohesion and a sense of shared purpose, which is protective for those contemplating suicide.
"People who are facing natural disasters become part of a larger community which gives them far greater support and assistance than they would have got had the disaster not occurred.
"Their neighbours speak to them, they can join in the community, they can help others.
"These effects, these transitory dips, will wear off, and Christchurch has probably now moved out of the first stage of the earthquake, where everyone gets together, and maybe the community is now beginning to move towards some degree of fatigue and disillusionment about the situation."
Judge MacLean's provisional Justice Ministry data shows a slight increase in the suicide rate from last year, to 12.6 per 100,000 population, but this is still significantly lower than the post-1985 peak of 15 per 100,000, reported in Health Ministry figures for 1995.
Judge MacLean began issuing up-to-date provisional figures last year, when he pointed out that more people died from suicide than in road accidents.
He also triggered debate on how suicide is reported - which has led to a review, not yet completed, of media reporting guidelines on suicide - and he suggested there could be a slight easing in what information coroners allow to be published after finding that a death was suicide.
The judge said yesterday that the public, especially parents of teenagers, wanted more information released on suicide cases for their own guidance as parents and "what to be looking out for" - but without full details of how a particular suicide was committed.
"The suicide toll is a really concerning commentary on our society, and I believe anything we can do to aid more accurate information can only be for the better."
Although the suicide rate was lower now than during much of the 1990s, it remained "stubbornly" similar to where it stood in recent years; new solutions were needed.
Tragedy by numbers
* Provisional 2010/11 suicide rate - 12.7
* Provisional 2009/10 - 12.3
* Highest annual rate, 1995 - 15
* Highest group by age and gender, 2010/11: men, age 20-24 - 31.7
* Highest female age group, 2010/11: age 50-54 - 11.1
* Later-teen rates, age 15-19 - males, 24.5; females, 10.4
* Highest rate by ethnicity: Maori - 17.9
Note - rates are per 100,000 population