"This supplements the variety of tactical options that are already available to us during callouts, as the rounds provide a mid-range option that helps enhance staff and public safety."
The sponge round is designed to be fired from a 40mm gas launcher, a product already used by STG and AOS.
It can be used at "extremely" close range with no increased risk of injury, police said, as the 40mm projectile was designed to spread its energy across 4.5 times the surface area.
"While the round does cause pain, bruising and abrasions, there is a wealth of international medical evidence that shows the risk of serious or life-threatening injury is extremely low" Mr Dunstan said.
However, if it helped police to resolve an armed situation safely without using firearms, its use was justified, he said.
The round wouldn't be replacing other tactical options.
"While the sponge round is a welcome addition to the range of tools currently available, it's important to stress that no single tactical option is always necessarily fully effective."