Normal school bus services in the area and the Northern Express were not affected.
Just after 9am, authorities sent out another notice announcing that the services were returning to its normal schedule.
"Thank you for your understanding and apologies for any convenience.''
First Union spokesman Jared Abbott said it was not aware of this strike action.
"Right now, the company is refusing to mediate with its drivers regarding health and safety related to hours worked.
"We know the drivers are very frustrated and the company needs to resolve this issue as soon as possible for the sake of these drivers and for the public's sake," he said.
According to Auckland Transport, the routes affected included: 82, 101, 105, 110, 129, 801, 802, 805, 806, 807, 814, 842, 843, 923 & 924.
Authorities said the Northern Express services are also not affected by the strike.
A member of the public, Arran Davis, tweeted that the real-time boards had not been updated.
"Might want to update the boards. I'm with 50 [people]...waiting.''
Another Twitter user said people had been queuing for buses since 7.30am, and were still waiting. "Not good," he added.