Nearly 20 Tasmanians who have COVID-19 were incorrectly told they tested negative on their PCR tests.
Tasmania's Health Commander Kathrine Morgan-Wicks has confirmed 19 people were on Tuesday wrongly notified.
The department said the error was corrected within three hours.
Ms Morgan-Wicks said the RHH Laboratory was improving its system to ensure another mistake won't happen.
"On behalf of the Department of Health, I apologise for the error and for any inconvenience caused to the recipients of the incorrect results," she said.
© AAP 2022