The measures were announced as members of the European Clubs Association (ECA), which represents more than 200 clubs, were warned at a meeting in Geneva that some of them were not taking the new rules seriously.
"ECA members unanimously endorsed the financial fair play project back in 2010," said ECA president Karl-Heinz Rummenigge, who is also Bayern Munich's chief executive.
"However, it seems that quite a few clubs have not understood the message. Time has come to take the new rules seriously. ECA will continue to support financial fair play."
"I am still very worried about the current situation," he told clubs, according to an ECA statement.
"The Financial Fair Play Regulations are known for more than two years, but I have the impression that some clubs still need to do their homework."
UEFA said the 23 clubs, who also include Qatari-owned La Liga side Malaga and Portugal's Sporting, were found to have "important" overdue payments to other teams, their own employees or social and tax authorities.
The clubs will have to provide an updated report on Sept. 30 to Dehaene's committee.
"This... measure will remain in force until all identified balances have been settled in full or until a final decision by the [UEFA committee] is taken," said UEFA.
Among other clubs under investigation are Dinamo Bucharest and Rapid Bucharest of Romania, Turkey's Fenerbahce and Serbia's Partizan Belgrade.
All are involved in this season's UEFA competitions.
There were no clubs from the English Premier League, German Bundesliga, Italy's Serie A or France's Ligue 1 among the clubs named.
"RESTRUCTURING PROCESS"
"One month ago, an internal restructuring process was started to guarantee the future viability of the club," Malaga said in a statement.
"In this process, the club has normalised its financial situation with other clubs, employees and players and has started negotiations with the tax service, with which the club has not reached a final agreement although we have reduced the amount owed considerably in the last month."
