An investigation's under way after a company that services IT systems for Northern DHBs has found unusual technology activity

HealthAlliance says it picked up issues during routine security monitoring.

The tech provider says so far there's been no impact to health services, and IT for all Northern DHBs are functioning normally.

It says there's nothing to link the activity to the recent cyber security hack that crippled Waikato DHB.

The Privacy Commissioner's office says it was notified by Counties Manukau DHB on Wednesday, and is monitoring the situation.