While hundreds of police officers will be visible at Friday's national memorial in Christchurch, some will be staying in the shadows.
Between 40,000 and 80,000 people are expected to attend the service in Hagley Park, two weeks on from New Zealand's worst-ever terror attack.
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"This is one of our largest security operations, obviously one of the reasons being that the country is still under a national threat level of high," Police Commissioner Mike Bush told The AM Show on Friday morning.
"But we're here, we have hundreds of officers deployed today to ensure people are safe when they come here, but also feel safe to come here to respect all of the victims of his horrendous terrorist event."
Officers from Australia have been flown over to help make sure there's no repeat of March 15, when a suspected white nationalist opened fire in two of the city's mosques, leaving 50 dead. But not all of them will be on patrol.
"There will be some you don't see, obviously," said Bush. "There will be roles that are a little bit more covert."
The identities of the two officers that apprehended the gunman remain a secret. Bush said their stories will be told one day, but not yet, as the investigation continues.
"They are very humble, very experienced police officers. They put their lives at risk knowing that they need to stop this person going on to do more harm. We are just so proud of what they did. It's a wonderful story - hopefully at some stage it could be told, but not at this point."
There have been questions whether the police could have stopped the gunman before he reached the Linwood Islamic Centre, which was seven kilometres from the Al Noor Mosque, where he first opened fire.
On Monday, ACT MP David Seymour said he understood "police arrived at the Masjid Al Noor mosque while the attacker was still there but did not prevent him from leaving", and called for their response to be included in the royal commission scrutinising New Zealand's security and intelligence agencies.
"It is not a pleasant question, but it needs to be asked how a single perpetrator was able to move from one site, drive seven kilometres through a major city to another site, and commit further atrocities, then escape the second site as well. I'm not aware of any terror attack worldwide where a single terrorist was able to move to multiple sites."
A police spokeswoman told NZME on Thursday the first officers arrived a minute after the gunman had left Al Noor, where 42 were killed. Eight of those shot at Linwood died.
Bush said they responded "as quickly and professionally as humanly possible".
"The public of New Zealand should really acknowledge, and do acknowledge from what I'm seeing, the wonderful work that they did.
"But at the same time the public have got a right to be reassured we did everything humanly possible. At some stage in the near future, we'll be putting out a very detailed timeline of exactly how that occurred."
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