He refused to say whether Simi had been stood down immediately after the allegation was made.
The victim, whose details are suppressed to protect her, said: "His actions left me feeling completely violated."
Simi had been supervising her while she learned to drive a bus and late one afternoon they arrived at a Great South Rd stop 20 minutes early.
The court was told Simi walked her to the back seats of the vehicle, took her by both hands, sat down next to her and took her sunglasses off.
"You kissed her on the lips with your right hand holding the side of her face," Judge Philip Recordon said.
She rushed out of the bus and when Simi continued to make advances, she jumped back into the driver's seat and drove the pair to Southmall station. When she stopped the bus, Simi put his hand under her shirt and touched her stomach.
"There was a position of authority and that's a significant factor," Judge Recordon said.
"You took advantage of an opportunity and for whatever reason, you essentially preyed on this young lady."
The judge said there was a possibility Simi may lose his job "but I hope not, for your sake and the sake of your family".
A New Zealand Transport Agency spokeswoman said a decision was yet to be made on whether Simi would be stripped of his passenger licence.
The Herald revealed yesterday that 346 passenger licences had been declined, revoked or expired due to sex convictions between January 2006 and December 2015.
Bus and Coach Association chief executive Barry Kidd said the strict P-licensing protocol should address any potential concerns of the public.
"An incident like this ... in no way reflects on anyone other than this particular individual."
Simi was ordered to pay the victim $6000 and was sentenced to 60 hours community work and 12 months' supervision.