New Zealand Social Welfare Number

Detects New Zealand Social Welfare Number patterns. This pattern is based on a Microsoft Purview built-in sensitive information type. Due to the generic numeric format, corroborative evidence keywords are essential for reliable detection.

Type

regex

Engine

universal

Confidence

medium

Confidence justification

Medium confidence: nine-digit numbers are common in many contexts. Keywords such as 'social welfare' or 'MSD' are required for reliable detection. Context label evidence plus explicit template/example exclusion improves precision for high-risk identifiers. Added context gating and exclusion rules improve precision and reduce incidental matches.

Detection quality

Verified

Jurisdictions

nz

Regulations

Privacy Act 2020 (NZ)

Frameworks

ISO 27001, ISO 27701

Data categories

pii, government-id

Scope

narrow

Risk rating

5

Platform compatibility

Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Compatible, Netskope: Compatible

Pattern

\b\d{9}\b

Corroborative evidence keywords

social welfare, MSD, beneficiary, welfare number, client number, [object Object], benefit number, benefit recipient, Ministry of Social Development, social security, welfare client, WINZ, Work and Income, data record, database record, record set, data extract, data export, database table, spreadsheet (+17 more)

Proximity: 300 characters

Should match

• 123456789 — Nine-digit social welfare number format
• 987654321 — Nine-digit MSD client number
• 112233445 — Nine-digit beneficiary identifier

Should not match

• 12345678 — Eight digits, too short for welfare number
• 1234567890 — Ten digits, exceeds welfare number format
• sample template placeholder number 12345678 — Template/sample context negative — the embedded number is 8 digits, one short of the required 9, so the universal-engine top-level regex correctly does not match it (template gating is a Purview-tier NOT-group concern, not expressible in a bare regex)
• template example placeholder record identifier — Template/sample context should be excluded even when anchor words are present

Known false positives

• Generic numeric sequences matching the digit pattern in non-health contexts Mitigation: Require corroborative evidence keywords within the proximity window to distinguish health identifiers from general numeric data.
• Reference numbers or account identifiers from other domains with similar digit counts Mitigation: Layer with document classification to prioritise matches in health and medical documents.

References

• New Zealand Social Welfare Number entity definition - Microsoft Learn