The United States could improve how it spots and prevents risks in the financial system from turning into destabilising crises, a global regulatory task force said on Tuesday.
The Financial Stability Board (FSB) said the world's top insurance market could also streamline supervision of the sector by centralising powers currently held at state level.
The FSB coordinates financial rules for the world's top 20 economies (G20) and will update leaders next month on progress in making financial systems safer and less likely to need taxpayer bailouts for banks again in future crises.
The watchdog said in its review of certain new U.S. rules that the United States has a complex and fragmented supervisory structure with many state and federal regulators.
But the new U.S. Financial Stability Oversight Council (FSOC), set up to spot broader risks regulators across the world missed ahead of the 2007-09 financial crisis, "represents a reasonable approach" to coordinated oversight, the FSB said.
FSOC, like the European Systemic Risk Board and the Financial Policy Committee in Britain, are a new breed of so-called "macroprudential" watchdogs tasked with sniffing out housing bubbles and other risks before they get out of control.
But FSOC's broad membership might affect its ability to act quickly and more clarity is needed on how it operates so that it becomes "greater than the sum of its parts", the FSB said.
"While the risks or threats to financial stability are already identified in FSOC annual reports, those risks are not analysed in detail and are not prioritised in terms of their significance or their immediacy," it added.
The FSB also has concerns over how U.S. insurers are supervised by a "multiplicity of state regulations" and that reforms such as setting up the Federal Insurance Office, don't go far enough as most powers are still held at state level.
"The U.S. authorities should carefully consider and provide recommendations to Congress as to whether migration towards a more federal and streamlined structure may be a more effective means of achieving greater regulatory uniformity," it added.
Checks are also needed to see if insurers hold enough capital to back their life insurance products, the FSB said.
The U.S system for capitalising insurers made it difficult for investors to compare risks across the sector or with international rivals, the review, chaired by Andreas Dombret of the Bundesbank, added.
A U.S. Treasury spokeswoman said that as a member of the FSB, it welcomed the review.
"We agree with the findings that the establishment of the Financial Stability Oversight Council, the Office of Financial Research and Federal Insurance Office represent important steps to enhance stability of the financial system," she said.
The review said the United States has made "substantial" progress in strengthening oversight of systemically important financial market infrastructure such as clearing houses.
All G20 members are committed to having their financial systems reviewed regularly by their peers.