Over a thousand people complained to the National Transport Authority about taxis last year.
The 15 percent increase included gripes about dirty or smelly cars, roadworthiness and overcharging.
Almost two in every five complaints related to driver behaviour.
One female passenger said her driver became aggressive when she took a photo of his dashboard ID.
One person reported concerns there were no working indicators, after front seat passenger was asked to indicate manually out of the window.
That case was investigated but no evidence of an offence was found.