One Nation senator Malcolm Roberts made the claim in an X (formerly Twitter) post on January 30. Sharing a screenshot of a January 24 ABC News Instagram post about Australia’s population hitting 27 million, Senator Roberts wrote: “Bigger Australia - what does the 27 million milestone mean for you?”.

Following a claim that it represented increased housing and living costs, more traffic and more job competition, he continued: “...And this doesn't include the 2.7 million visa holders in Australia...”

Senator Roberts concluded his post with: “We need Net Zero Immigration until housing and infrastructure can catch up”.

When asked to clarify the claim about visa holders, a representative for Senator Roberts directed AAP FactCheck to the Australia Bureau of Statistics (ABS) population clock.

“This is essentially a combination of natural population increase and net overseas migration (NOM),” the representative said.

He said it was “the Senator's understanding” that the 2.7 million temporary and visitor visa holders are not included.

That is incorrect.

The ABS population clock is calculated by using what is called the estimated resident population (ERP) as its base.

This is calculated quarterly, with the most recent published figures for the quarter ending June 30, 2023.

The clock then projects the population by adding/subtracting to the ERP average birth/death rates and average rates for those leaving/arriving in Australia. As this archived link shows, the clock ticked past 27 million on January 24.

In calculating the ERP, the ABS includes various sources of data, including births, deaths and overseas migration.

To calculate overseas migration, the ABS receives data on the number and types of visas from the Department of Home Affairs.

However, the type of visa does not determine whether someone is included in the ERP. Instead, this is calculated using what is called the 12/16 rule.

This is, a person is added to the ERP if they have been, or are expected to be, in Australia for 12 months or more over a 16-month period.

So while Senator Roberts is correct that there were around 2.7 million temporary visa holders - there were 2.76 million at December 31, 2023 (see table, cell V28) - they are not automatically excluded from the ERP.

In fact, the ABS told AAP FactCheck the majority would be included.

While the type of visa does not determine inclusion in the population count, reasonable assumptions can be made about their status, the ABS said.

For example, many of the 547,075 student visas (see table, cell V20) in Australia as of December, 31 would be for students staying to complete a three-year-plus degree and therefore would be included under the 12/16 rule.

The “Special Category” is the largest and contains New Zealand citizens in Australia under the subclass 444 visa.

This visa enables New Zealanders to remain in Australia indefinitely, so it would be expected the vast majority of the 701,868 (cell V19) , as counted in December 2023, will have been living here for many years - and therefore also included under the 12/16 rule.

The ABS told AAP FactCheck that the group likely to have the largest contribution to those not included in the ERP are the Visitor visa holders, which as those on a Visitor visa can only stay in the country for three months. Visitor visas numbered 601,051 in December 2023 (cell V21). This was the highest quarterly total since before the pandemic.

While some visitor visa holders may transfer to another visa, it would be reasonable to expect the majority to be in Australia for a short stay and therefore not included in the ERP, the ABS said.

The ABS said the visitor visa group would likely be the only group where the majority are not counted in the ERP.