"Frankly I think most New Zealanders would be appalled at the practices of some third-tier lenders."
Faafoi said he acknowledged some people needed to borrow, but excessive interest rates and fees were making it harder.
Faafoi said he planned to introduce the legislation by either the end of this year or early next year.
Faafoi is also ramping up his fight against wheel clampers, who charge exorbitant fees.
He has called for a cap on the amount companies could charge to remove a clamp and indicated a ban would be unlikely.
However, all options are available to Cabinet when considering legislation, he told the Herald this month.
"We're still going through the process of finalising exactly where we'll land on that, whether it's an outright ban or we regulate that and cap the price of a fee to remove a clamp," he said.