The payday lender has launched an immediate consultation with staff at risk of redundancy, which will run for 30 days.
Chairman Andy Haste said Wonga will become smaller and less profitable in the near term as it introduces changes to make sure it lends “fairly and responsibly”.
He said: “Our focus is on creating a business that meets the demand for short-term credit sustainably and responsibly, resulting in good customer outcomes.
“We’ve already made significant changes, including appointing a new leadership team, implementing a new risk decision engine and tightening our lending criteria.
“However, Wonga can no longer sustain its high cost base which must be significantly reduced to reflect our evolving business and market.
“Regrettably, this means we’ve had to take tough but necessary decisions about the size of our workforce.
“We appreciate how difficult this period will be for all of our colleagues, and we’ll support them throughout the consultation process.”