In a statement, a police spokeswoman said nearly all dog deployments occurred when people had committed offences and run away, or were in possession of weapons and confronting police, and in most cases the use of pepper spray or a Taser was impractical.
"The majority of the incidents our dogs are responding to often involve an offender who is armed, unpredictable and poses a high risk to themselves, the community or our staff.
"Our staff are responding to highly complex situations which can escalate rapidly.
"When use of force is unavoidable, it is necessary to take steps to resolve situations before there is further risk of serious harm or worse to our staff, the parties involved and the wider public."
All dog handlers must issue a loud clear challenge to an offender advising the dog would be released if they did not comply, the spokeswoman said.
"We are acutely aware of the impact our dogs can have when biting someone.
"Our dogs and dog handlers receive very robust training and are regularly validated throughout their working life."
All dog bite cases were reviewed by a dog handler's supervisor and a commissioned officer of police.
Any serious bites were referred to the Independent Police Complaints Authority.
Dogs undergo a 37-week training course before becoming operational.
Once operational, they must undergo a minimum of eight mandatory training days, as well as requiring district certification and annual national certification, which is carried out by an independent reviewer.