The company's other drivers had been tested since the positive result and all had come back negative so far, although some results were yet to come, he said.
The buses were cleaned every day but those driven by the man who tested positive had been taken off the road for deep cleaning.
Ritchie said the driver was last at work two to three days ago and was now in isolation.
He did not believe it was likely any passengers would be affected as the front part of the bus where the driver sits was blocked off and passengers now had to enter via the back door.
Auckland Transport was working with public health officials to identify passengers on the buses driven by him as a precaution, he said.
Auckland regional public health said there were no close contacts from the bus trips on September 3 and 4 between 5.30am-1pm and 4-6.15pm. The driver was not symptomatic at the time, and was also wearing a mask.
There were no cash transactions and passengers used AT HOP cards. The staff who drove the bus after the case have been asked to be tested and CCTV footage of the bus depot is being reviewed to determine if any other staff members are close contacts, Auckland Regional Public Health said.
The case was linked to the existing Auckland cluster and the bus driver did not contract Covid-19 while working.
Anyone who travelled on the bus with the driver at these times was a casual contact, at low risk of developing the virus. They did not have to self-isolate, but should get tested if they developed symptoms of Covid-19.
The Auckland Regional Public Health Service said the case highlighted the importance of all public transport passengers scanning the QR codes with the NZ Covid Tracer app in addition to swiping their AT HOP cards as it provided another way of alerting people when they may have been exposed to Covid-19.
The bus journeys
Thursday September 3 and Friday September 4
05:40am - Albany Station To Britomart (Lower Albert St) (05:40 - 06:06)
06:15am - Britomart (Lower Albert St) To Hibiscus Coast Station (06:15 - 06:59)
07:15am - Hibiscus Coast Station To Britomart (Lower Albert) AM Peak (07:15 - 08:00)
08:42am - Hibiscus Coast Station To Britomart (Lower Albert) AM Peak (08:42 - 09:26)
11:05am - Hibiscus Coast Station To Britomart (Lower Albert St) (11:05 - 11:48)
11:55am - Britomart (Lower Albert St) To Albany Station (11:55 - 12:24)
12:30pm - Albany Station To -Britomart (Lower Albert St) (12:30 - 12:58)
16:04pm - Britomart (Lower Albert St) To Albany Stn (16:04 - 16:36)
16:43pm - Albany Station To Britomart (Lower Albert St) (16:43 - 17:15)
17:37pm - Britomart (Lower Albert St) To Albany Station (17:37 - 18:13)
- Due to city centre capital works, the Britomart (Lower Albert St) collection point for the NX service is on Customs St.