A second dog, which was also living at a property owned by the embassy in Stirling and involved in at least one of the attacks, was deported back to the US on December 18, a government spokeswoman said. It is believed to now be living with relatives of its diplomat owner.

The news comes amid a push to swell the ranks of the capital's dog rangers in 2018.

It is understood the ACT's Domestic Animal Services has been running with a limited staff of about four dog attack investigators since at least October.

The government began recruiting for a further eight staff to join them after the fatal mauling of a Watson woman on October 25 brought the issue of dog attacks in Canberra to a head.

The latest annual reports also show a fourfold increase in dog attack investigations in just five years.

ACT Minister for Transport and City Services Meegan Fitzharris said the government took dog attacks "very seriously" and would soon be undertaking a review of Domestic Animal Services as well as tougher dangerous dog laws introduced late last year.

"Since that legislation came into force we have already seen a number of dogs impounded and control orders issued," Ms Fitzharris said.

Community support for the reform, which gives authorities increased powers to seize dogs they deem dangerous, was also strong, she said.

The new rangers are expected to begin later this month.

Both German Shepherds involved in last year's attacks were owned by a US diplomat, authorities confirmed on Thursday.

They were seized by ACT Domestic Animal Services on November 29, after attacking a 15-year-old girl on the way to her high school formal, as well as her father.

In October, the same dogs escaped the Lochee Place property and attacked two women and a four-year-old girl, but investigations were initially slowed due to diplomatic considerations.

Ms Fitzharris said, while she was focussed on making Canberra a pet-friendly city, 2018 would also see increased enforcement around responsible pet ownership.

"We will look at where our off leash areas are, and whether we have the balance right," she said.

"We will also open a new dog park in Weston Creek."