Payday lenders are failing to live up to the "spirit or the letter" of codes they signed up to last year, ministers have said.
The comments come ahead of a summit, bringing together payday lenders, regulators, charities and ministers.
Consumer minister Jo Swinson, who hosts Monday's summit, said lenders must do "much more" to protect consumers.
Payday firms offer short-term loans at high interest rates but are accused of leading people into more debt.
The industry, worth £2bn, was referred to the Competition Commission by the Office of Fair Trading last Thursday.
The lenders say they are already changing their practices, but will be overseen by a new regulator, the Financial Conduct Authority, from next April.
In a statement before the meeting Ms Swinson said: "Evidence of significant widespread problems in the payday market is concerning. Earlier this year we and the regulators announced a strong action plan with immediate and longer term measures.
"Today we will be taking stock of progress and looking at what we do next to better protect consumers and address these problems.
'Get house in order'
"I have long had specific concerns about the advertising of payday loans and my department has commissioned research to look into the effect of payday lending advertising on consumer behaviour."
At the meeting, the OFT and Financial Conduct Authority will give updates on enforcement action and potential changes to regulations.
"But the industry needs to do so much more to get its house in order, particularly in terms of protecting vulnerable consumers in financial difficulty," Ms Swinson said.
"I am concerned that the lenders are not living to the spirit or the letter of the codes of practice that they signed up to last year," she added.
Last week, the OFT said it found that customers found it difficult to identify or compare the full cost of payday loans.
It added that there were barriers to switching between lenders when loans were rolled over.
The OFT said it was also concerned that competition was based on speed rather than cost.
During its investigation, the OFT found language used by lenders to bring in customers included the phrases: "Instant cash", "Loan guaranteed" and "No questions asked".
The OFT described the problems as "deep-rooted" and said some firms' business models appeared to be based around customers taking out loans which they were forced to roll over because they could not afford them.
This then left the customer trapped with that firm because they would struggle to switch to anyone else.
Lord Freud, minister for welfare reform, said: "The unscrupulous practices of some payday lenders can place vulnerable people at risk.
"I am concerned about some companies using Continuous Payment Authority to access borrowers' bank accounts inappropriately and excessively. I am determined that payday lenders should not be able to misuse this system to recoup funds from vital benefit payments that should be used for essential spending, such as utility bills and rent.
"We are working hard to end financial exclusion, which is often the reason people turn to payday lenders. We are investing £38m in credit unions to provide a good value alternative to help people save and access loans if they need them.
"I hope this summit will address some of the problems with the industry, so lenders can meet their obligations to their customers."
The body which represents payday lenders, the Consumer Finance Association, has said it welcomed well-designed regulation but was unhappy about the scrutiny that the industry had received.