Froggatt was critical that he was only notified of the situation on Sunday.
He also claimed that the majority of staff at NZ Bus and City Depot have been left in the dark.
"It's five days too late, it should have been sent out immediately to ensure drivers could take extra care," said Froggatt.
"The risk to all employees is immense as not only City Depot employees are affected but all the other drivers who had a meal break at City Depot."
Froggatt's concerns also extended to workers who cleaned and serviced the buses.
In an email to the union NZ Bus stated that affected areas and buses had been deep cleaned and that close contacts had been identified and were isolating.
An NZ Bus spokesperson said the driver worked over two days between January 3 and 4 and believe he was infectious for two days.
"He was unwell on Wednesday 5th January and went to have a Covid test.
"He has been absent from work since. The positive result was received by the driver on Friday 7th January 2021, at which point he then notified NZ Bus."
NZ Bus has six other depots located in Auckland and depots in Wellington and Tauranga.
Staff who were considered to be close contacts of the driver are now isolating and awaiting test results, while the Ministry of Health will contact passengers who travelled on Route 321.
However, NZ Bus believes there were only five passengers who travelled with the infected driver.
Meanwhile, it comes as people who were in an Orewa nail bar are being told to test immediately and self-isolate for five days after a Covid-infected person was in the premises last Wednesday afternoon.
The Ministry of Health added Khoi Nails Spa to the locations of interest as a close-contact premises.
People who visited the spa last Wednesday between 1.26pm and 2.30pm are required to self-isolate, test immediately and then again on day 5 after exposure at this location.
Today health officials said there were 27 people in the community with Covid, including 16 people in Auckland.
