Shadow Minister for Indigenous Australians, Kerrynne Liddle, says it is "not good enough" that applicants for Indigenous-only jobs and grants at Services Australia can bypass long-standing established tests regarding Aboriginality.

The comments come amid growing debate about how Indigenous identity is verified, with several Coalition senators, including Jacinta Nampijinpa Price, condemning so-called "box tickers" and claiming there has been an "increase" in people identifying as Indigenous.

At Senate Estimates, the National Indigenous Australians Agency (NIAA) confirmed that some government departments — including Services Australia — accept a statutory declaration as proof of Aboriginality instead of the three-part test established in the Mabo case. That test requires evidence of biological descent, self-identification, and community recognition by Elders or traditional authority.

In a statement, Senator Liddle said Services Australia only requires two statutory declarations: one from the applicant and another from either an Indigenous Australian Public Service employee or an Indigenous service provider, such as a university Indigenous support unit or an Aboriginal medical service.

NIAA Acting CEO Julie-Ann Guivarra told estimates the agency was not consulted about Services Australia's decision. She said while many departments use the three-part test, "a number of agencies… have, from time to time, accepted statutory declarations from people" when it comes to "assessing Indigeneity".

"There are a range of reasons why an individual may choose to put forward a stat dec as opposed to other documentation supporting their Aboriginal and Torres Strait Islander descent," she said, noting some Stolen Generations survivors lack access to birth certificates or family records.

"That issue around the first limb of the three-part test being a person of Aboriginal and Torres Strait Islander descent — they may not be able to provide that evidence in and of itself because they don't have the documentation to support it."

Senator Liddle said the system has "serious implications for service delivery".

"The 25 per cent increase in the number of people that tick that box between one census and the next has significant implications on service delivery, but none more so than the most vulnerable person who has experienced disadvantage their entire lives," she said.

"They're not even going to get in that line anymore for any of the services because they simply can't navigate it."

In response, Minister for Indigenous Australians, Malarndirri McCarthy, said whilst she was "mindful" of the complexities surrounding people's discovery of their Aboriginal heritage, she committed to "having a look" into Senator Liddle's concerns.

Senator Liddle later doubled down, calling the government's "lax approach" unacceptable in a statement on Tuesday afternoon. She said the lack of consultation with the NIAA "will impede the most vulnerable Aboriginal and Torres Strait Islander people from accessing the services they need and jobs that could change their lives".

"Minister Malarndirri McCarthy has committed to look into the increasing use of statutory declaration[s], but it should have never been allowed to creep into being commonplace," Senator Liddle said.

"At a time when Closing the Gap is not on track, the work has not even been done to understand the implications of an increase in 25 per cent more people ticking the Indigeneity box in the last Australian Census.

"I respect people find out about their identity much later in life, but ancestry and identity are not the same thing."

Earlier this year, Senator Price raised similar concerns, arguing in the Senate that Closing the Gap data is incomplete and "lacking on increasing box-tickers".

"That is, self-identifying Indigenous Australians whose ties to Indigeneity are tenuous at best or non-existent at worse," she said in February.

"Aside from causing data deficiencies, the box-tickers are skewing our policy conversations as opinions of box-ticking elites are often favoured over true Indigenous knowledge holders.

"This is a serious problem. It's contaminating the data and the policies we create, and marginalised Indigenous Australians ultimately suffer."