'Crate' man from alleged stabbing rampage in Sydney said he grabbed what he could

The hero who held down an alleged knife-man on a rampage in Sydney's CBD this week has spoken for the first time.

Jase Shore, a former soldier, is being hailed as the master of improvisation after pinning down alleged attacker Mert Ney with a milk crate.

"I was coming around a corner, I think it just, it was just something there, at my feet, within arm's reach, while I could still see the offender, so it was one of the only things I could grab at the time," he told 9News.

"My initial thought was to keep distance between me and him, and the blade really, or to try to get the blade out and knock him down with that object."

Mr Shore grabbed the milk crate and helped restrain Ney along with a number of other onlookers, including a lawyer who chased the alleged assailant down the street with a chair.

"To be honest he wasn't really saying too much he looked troubled, and I think that was kind of the main point, we just asked everybody in the area just to sort of keep clear."

Ney remains under police guard in hospital after having surgery for cuts to his legs.

He's expected to undergo a mental health assessment and has yet to be charged over the alleged spree.

The police investigation is being matched by a government review amid concerns Ney, who was apparently suicidal, was able to roam the streets.