An independent security review has found there was nothing the Ministry of Social Development could have done to prevent the Ashburton Work and Income shootings.
Russell John Tully is charged with murdering Peggy Noble and Leigh Cleveland and the attempted murders of Lindy Curtis and Kim Adams on 1 September.
The first phase of the review considered whether there were any practicable steps the Ministry could or should have taken that would have prevented the event. The lead reviewers - former police commissioner Rob Robinson and Murray Jack of Deloitte NZ - did not identify any such steps.
Speaking at the report's release today, the ministry's chief executive Brendan Boyle said the organisation was still hurting from the incident and feeling for the families affected.
"It is extremely difficult to design a system to prevent someone who is determined to inflict extreme and violent harm, but we have made changes to enhance security for staff and the public," he said.
Mr Boyle said the ministry had already moved to implement the review's recommendations, including taking a tougher approach to threatening behaviour. He said he believed staff had not taken threatening behaviour seriously enough in the past.
Since the shootings, there have been 200 threats against staff, resulting in 70 people being trespassed.
"Some of the threats have been in relation to the Ashburton incident so clearly there's a trigger there", Mr Boyle said.
"Some of it is the fact that our risk appetite and our tolerance levels have clearly changed off the back of the event. We've said very clearly to staff, 'This is not acceptable behaviour. It wouldn't be acceptable if it was happening in other workplaces or in a normal public setting, so why should it be acceptable at Work and Income?'"
Mr Boyle said while the review found there was nothing the ministry could have done to avert the tragedy, there was more work to do around staff training and information sharing.
He said the ministry also needed to re-set the behaviour of clients, and make them understand that threatening behaviour will be referred to police.
Following the shootings, the ministry introduced extra security guards and controlled access to its public-facing sites. The review recommended these measures remain in place until phase two of the review is completed, which Mr Boyle confirmed would happen.
The second phase of the review will look at all ministry workplaces and will recommend any changes to ensure the physical safety of staff and members of the public. It is also being carried out by Mr Robinson and Mr Jack.
Summary of report
Today's report recommends that the Ministry of Social Development enhances:
Mr Boyle said the ministry accepted those new recommendations and was addressing them immediately.
The report said that immediately after the shootings, the ministry implemented 10 measures to assure staff confidence and improve the safety of staff and visitors at public-facing sites. These measures included: