City of Rockingham councillor Matt Whitfield said the troop were deemed a safety issue for pedestrians and road users after the incident and the fence was consequently erected by the developer, Spatial Property Group.

Cr Whitfield said Spatial had originally proposed for the kangaroos to be "humanely tranquillised and euthanised" as part of a management plan despite the city’s request the animals be relocated.

The Department of Biodiversity Conservation and Attractions is responsible for licensing fauna management activities and authorised the euthanasia of the kangaroos.

Cr Whitfield said the city and developer were now working closely to find an alternate solution due to the widespread opposition to killing the animals.

"The city expressed its concerns to both DBCA and the developer regarding this course of action, reiterating the preference for kangaroos to be relocated rather than euthanised," he said.

"However, DBCA has advised that euthanasia is an acceptable management measure and therefore maintains its approval of the proposed action."

Cr Whitfield said he understood euthanising kangaroos was a "very common" practice to make way for development but an alternate solution should be found.

As a temporary solution, Cr Whitfield suggested the kangaroos be herd across to an open parcel of land across Baldivis Road until a more permanent and appropriate solution was found.

"In an ideal world the roos would be relocated properly to another site locally (we are fortunate that we have hundreds of acres of protected areas in Baldivis such as the Tamworth swamp, children’s forest etc) but there is no guarantee of the success as the welfare of the roos could be compromised and ultimately DBCA have not given permission for this to happen,” he said.

"I understand that people want development but I don’t want families and young kids to see the kangaroos be killed when it happens.

"Euthanising is a cheaper option for the developer but they are aware of the community’s feeling on this.

"But nothing can happen unless the department changes its plan as it stands."

Baldivis MLA Reece Whitby agreed a "much better" solution could be found for the native animals.

"Action needs to be taken much sooner and the aim should be trying to find a place to relocate them where the kangaroos can safely reestablish themselves," he said.

"This mob has lived in close proximity to residents for a number of years so it’s understandable there is concern about their welfare and their future."

Mr Whitby said he had received information from DBCA which stated the challenges faced when kangaroos are displaced from residential developments.

"Relocation of large numbers of kangaroos can result in poor animal welfare outcomes as the areas into which they are placed already have kangaroo populations that are using all available resources," the DBCA told Mr Whitby.

"The relocation process itself can also cause stress to the animals, which can result in their death despite best efforts.

"DBCA understood that there were exit points available to the kangaroos along Baldivis Road and thus, they were not entrapped."

DBCA has been contacted for comment.