A large dent is visible on the left hand side of the Auckland Transport Metro labelled bus, just behind the front wheel.
A shop assistant at a store nearby said the incident happened outside the Howick & Eastern Bus depot on Ti Rakau Dr.
Another worker at a nearby store said a body could be seen between barriers on the road. It was covered by a sheet.
She said quite a few police were in attendance and no one was being let in or out of the cordoned area.
New Zealand Transport Agency alerted commuters that Ti Rakau Dr is closed in both directions, between Greenmount Dr and Huntington Dr.
NZTA said congestion was building and motorists should avoid the area or delay travel if possible.
Ti Rakau DR is said to be backed up to Reeves Rd and significant delays are being experienced on Harris and Cryers Rds and Greenmount Dr.
The Serious Crash Unit is in attendance.