The Covid-19 case at St Lukes that was being reinvestigated has now been linked to the existing cluster.
Eleven new cases of Covid-19 have been reported today, including two in managed isolation and quarantine facilities and nine in the community with links to the current outbreak.
Yesterday, the Auckland Regional Public Health Service had notified the public that a retail employee at St Lukes mall had worked there for a number of days while infectious with the virus.
The source of infection was under investigation yesterday, and today Director-General of Health Ashley Bloomfield confirmed the worker's case was linked to the existing cluster.
He said one line of inquiry was that the person may have been on the same bus with another case on the morning of 12 August - just before level 3 restrictions.
Regional public health has been working with bus companies to confirm that using Auckland Transport Hop card data.
Dr Bloomfield said other people on bus may have been at risk - and there will be contact tracing, isolation and testing - and the case underscored the importance of using masks on public transport.