Among the victims were Uber and taxi drivers and job applicants seeking employment.
Withers used several aliases while in Auckland and Christchurch, including pretending to be a lawyer and an owner of chauffeur, hotel and horse leasing businesses.
Judge Paul Kellar told the court that the serious aspect in the sorry tale was the scale of the offences and that the victims were unlikely to get their money back.
He said high levels of greed and selfishness were displayed.
An aggravating factor was the premeditated nature of the offences and sophisticated techniques used to defraud victims.
Some of the offending occurred while he was on electronically monitored bail.
Withers was diagnosed as showing a personality disorder with narcissistic traits.