A Sydney lab has told hundreds of people they did not have Covid when they in fact had tested positive, amid soaring infections in the area.
The mistake, which took place over the Christmas period, was due to a “data processing error”.
The Australian state of New South Wales is seeing rising infection numbers following the arrival of the hyper-infectious Omicron Covid variant.
Officials say an increase in swabbing tests has caused massive backlogs.
Some of those affected have expressed concern that they may have unknowingly infected their loved ones over Christmas.
The SydPath lab apologised in a statement on Tuesday and said the mistake, which affected 886 people in total, had happened as workers faced an “unprecedented” volume of tests.
It initially admitted earlier this week that it had erroneously told 400 people on Christmas Day that they did not have Covid. They were only notified about the mistake the following day.
The blunder grew when SydPath later revealed that hundreds more had been prematurely told they had tested negative, when their results had not yet been determined. On Tuesday, the lab said 486 people from this group had been confirmed as Covid-positive.