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That would mean some offices would be "locked down", Social Development Minister Paula Bennett said today.
Over the past few days the department had seen the best and worst of people, with some making threats against offices around the country, Ms Bennett said.
"We've taken those threats very seriously.
"In some circumstances that will mean us locking down sites - that means other people that genuinely need help are not able to get it as quickly or as efficiently as they require it.
"But those are the steps we are well prepared to take."
Ministry of Social Development chief executive Brendan Boyle said former police commissioner Robbie Robinson and Deloitte New Zealand chairman Murray Jack would be undertaking the review.
Earlier today, former Work and Income chief executive Christine Rankin said the possibility of a tragedy like the Ashburton shootings had always hung over staff.
Ms Rankin told TV3's Firstlinethat Work and Income staff deal with people in stressful situations that can't be "de-escalated or simply talked through".
"We've always thought that something like that could happen, it definitely hung over all of the staff there for a long period of time."
She said when she was chief executive someone drove a car through a Work and Income office in Flaxmere.
"It was very lucky that someone wasn't killed in that incident and that did give us a shock and thought about the reality of the thinking that something really big could happen."
Ms Rankin said that removing all barriers in offices in favour of open-plan style had decreased the number of incidents of violence.
"The minister and the chief executive must be really worried now about what they're going to be forced to do, because in most other parts of the world the staff are behind bulletproof glass," she said.
She said she hoped that New Zealand would not end up in that situation.
Russell John Tully has been charged with two counts of murder and one count of attempted murder.
Security has been beefed up at Work and Income offices nationwide.
One hundred security guards were being deployed at branches around the country after alleged threats in the aftermath of the Ashburton shootings.