The shooter killed the women on Friday at their Floreat home where his ex-wife was believed to have been staying, in what WA Premier Roger Cook has called a "chilling and horrific" attack.
Multiple media outlets have named the victims as 59-year-old Jennifer Petelczyc, who was a friend of the gunman's ex-wife, and her 18-year-old daughter Gretl.
The WA government is in the process of toughening its gun laws with a $64 million buyback scheme underway and legislative changes on foot to restrict the number of firearms people can own.
However, the crime has prompted the government to consider even stricter gun laws and to concede more needs to be done to combat family violence in the state.
On Monday, WA police said the killer, named in media as Mark Bombara, 63, was the holder of a gun licence.
Police did not confirm WA Today report that he owned a stash of 13 firearms.
The killer was known to police but did not have a history of violence, authorities have said.
Mr Cook on Sunday described the shooting as "senseless" and said the victims were innocent people who had died helping a friend in need.
He urged the community to reflect on the deaths, which he said were part of a "society-wide issue" of gendered violence.
"We all need to stand as one to condemn family and domestic violence," he told Perth radio station 6PR.
Police were called to the home in Perth's affluent western suburbs about 4.30pm on Friday after reports of gunshots, arriving as the last shot was fired.
Officers rushed the younger victim to Royal Perth Hospital but she could not be saved.