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
After the awards were overshadowed by an extraordinary error over the best film, ITV News breaks down exactly what went wrong.
The first section of the wide-ranging inquiry will focus on child migrants sent to parts of the British Empire who endured horrific abuse.
Broadcaster Paul O'Grady has accused young people who practise unprotected sex of shaming the memory of his friends who died from Aids.