Australian Medicare Number

Detects Australian Medicare card numbers, which are issued to Australian citizens and permanent residents for access to subsidised healthcare under the Medicare system. The number consists of 10 digits: the first digit is between 2 and 6, followed by 8 additional digits and a single check digit. Numbers are commonly formatted as groups of 4-5-1 digits separated by spaces or hyphens.

Type: regex
Engine: boost_regex
Confidence: high
Confidence justification: High confidence when corroborative evidence keywords are present. The leading digit constraint (2-6) and fixed 10-digit length reduce false positives compared to generic digit sequences. Combined with proximity keywords like "medicare" or "health insurance", this pattern reliably identifies Medicare numbers.
Detection quality: Verified
Jurisdictions: au
Regulations: HRIPA (Cth), IPA 2009 (Qld), My Health Records Act 2012 (Cth), NDB Scheme (Cth), Privacy Act 1988 (Cth)
Frameworks: ISO 27001, ISO 27701, SOC 2
Data categories: pii, phi, government-id
Scope: narrow
Risk rating: 9
Platform compatibility: Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Compatible

Pattern

\b[2-6]\d{3}[\s-]?\d{5}[\s-]?\d{1}\b

Corroborative evidence keywords

medicare, health insurance, medicare card, medicare number, medicare no, health insurance number, IHI, Individual Healthcare Identifier, healthcare identifier, HPI, HPI-I, HPI-O, provider identifier, AHPRA, registration number, prescriber number, PBS prescriber, pharmaceutical benefits, Medicare provider, provider number (+7 more)

Proximity: 300 characters

Should match

2123 45670 1 — Standard spaced format (4-5-1 grouping)
2123-45670-1 — Hyphen-separated format (4-5-1 grouping)
2123456701 — Continuous digits without separators

Should not match

1234 56789 0 — First digit is 1, which is outside the valid range of 2-6
7890 12345 6 — First digit is 7, which is outside the valid range of 2-6

Known false positives

Phone numbers starting with digits 2-6 Mitigation: Require corroborative evidence keywords within proximity window to confirm context as a Medicare number rather than a phone number.
Australian Business Number (ABN) digit subsequences that overlap with the Medicare pattern Mitigation: Use corroborative evidence to distinguish Medicare context from business-related contexts. Layer with ABN-specific detection to deprioritise overlapping matches.