The Financial Services Authority (FSA) has criticised firms for failing to send in details of advisers' qualifications.
The FSA gave firms a deadline of 29 January to send in the data, which firms are required to provide under the regulator's rules.
However, an FSA spokesperson said today that a "significant minority" of firms had failed to meet the deadline, and were now more than two weeks late with the data.
"These firms are breaking the rules and if they continue not to provide the data we will have to follow up further," said the spokesperson.
The FSA is also collecting data on advisers' levels of qualifications from accredited bodies. This data shows a much larger number of advisers as qualified than the incomplete data from firms, the FSA said.
Compiling details of advisers' qualifications forms one tranche of a series of thematic reviews the FSA is carrying out this year and in 2014.
The FSA is conducting four thematic reviews in three cycles beginning last month. It will publish its findings after each cycle.
Four areas will come under the scope of the regulator's investigations; professional standards, charging, description of services and independence and restricted offerings.
The FSA said 2013 will be a year of working with firms to make sure they are applying the new rules, and firms will be "given a chance" to adapt to the post-RDR world. Though if poor practice is still evident after the third cycle action may be taken against those seen to be lagging.
Annuity market worth £4bn in 2017
For ‘distress’ caused
Oversees £30bn of advised and D2C assets
Less than a third of top paid employees are women
£1bn business since inception