Australian Taxation Identifier

Identifies Australian Tax File Numbers (TFNs) — unique nine-digit identifiers issued by the Australian Taxation Office. Uses Func_australian_tax_file_number validator with AllDigitsSameFilter and TextMatchFilter to exclude known test values.

Type: regex
Engine: boost_regex
Confidence: high
Confidence justification: High confidence: the Func_australian_tax_file_number checksum validator combined with AllDigitsSameFilter and TextMatchFilter for known test values provides strong precision. The bare 9-digit regex is broad, but the integrated validator reduces false positives to near-zero.
Detection quality: Mixed
Jurisdictions: au
Regulations: AML/CTF Act (Cth), IPA 2009 (Qld), NDB Scheme (Cth), Privacy Act 1988 (Cth), SOCI Act 2018 (Cth)
Frameworks: ISO 27001, ISO 27701, PCI-DSS, SOC 2
Data categories: pii, financial, government-id
Scope: wide
Risk rating: 9
Platform compatibility: Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Compatible

Pattern

\b\d{3}[\s\-]?\d{3}[\s\-]?\d{3}\b

Corroborative evidence keywords

tax file number, TFN, tax file no, australian tax, taxfile, ATO, ID number, identification, ID card, license, permit, registration, certificate

Proximity: 300 characters

Should match

123 456 789 — Standard spaced format
123-456-789 — Hyphen-separated format
123456789 — Continuous digits

Should not match

12 345 678 — Only 8 digits in 2-3-3 grouping
1234567890 — 10 digits, too long
000000000 — Excluded by TextMatchFilter
111111111 — Excluded by AllDigitsSameFilter

Known false positives

Generic nine-digit reference codes, invoice numbers, or account identifiers. Mitigation: Require tax-specific keywords in proximity. Filters exclude trivial and test values.
Phone numbers formatted as nine consecutive digits. Mitigation: Layer with phone detection to deprioritise overlapping matches.