Richard Lloyd, the executive director of Which?, has told BBC Radio 5 Live Wonga has been in a "complete shambles, a mess of a credit sector" and "needs sorting out".
He will be among those giving evidence at today's select committee.
We need to see a much more urgent approach to getting the cost - in particular fees and charges that payday lenders hit people with - under control, capped, much tougher rules, much sooner about the way they advertise and the way they deal with people who are applying for their loans.
...They're advertising payday loans as a lifestyle choice.... a lot of costs of a payday loan are hidden away in the terms and conditions ... the way they get people into trouble is hitting people with fees and charges that aren't necessarily there in the advertising.
More top news
Controversial columnist Katie Hopkins has described her fear that she may die during brain surgery to cure her epilepsy.
A funeral is to be held outside in the US state of Georgia for Bobbi Kristina Brown, daughter of the late Whitney Houston and Bobbi Brown.
Experts have warned that Ash dieback's impact on millions of trees could have serious consequences for the landscape and wildlife.