"It read: 'All personal items left behind on this bus will now be shared equally between the driver, mechanic and cleaner'."
It was signed by James Presley-Sinatra, who caught the Ritchies' Takapuna-bound bus from the Bayswater ferry.
In a response to the letter, Ritchies said it immediately checked the bus and found the sign, "which was removed".
"We also tracked down the driver who had put the sign in his bus and are pleased to advise that he is no longer employed with the company."
The Herald approached North Shore Ritchies for further details, but were told to ring back on Monday when the manager returned.