He refuted claims that it was impossible to know whether global financial institutions were actually risky or sound and said banks were no more opaque than other businesses.
"Businesses can be opaque. They are complex. You don't know how aircraft engines work either," he said, referring to policymakers.
Dimon said regulators were also struggling to keep up with the new rules.
"I think a lot of regulators are also overwhelmed, they're overwhelmed with rules and regulations."
Dimon also peppered his strong words for policymakers with some praise for the Federal Reserve, which rode to the rescue after the collapse of Lehman Brothers in September 2008.
"I think they saved the system. They did, global, so it wasn't just the United States."
Dimon also suggested that banks had gotten an unfair rap and that many of the risky practices, such as the use of structured investment vehicles (SIVs) and the most-exotic derivatives had stopped.
"Some banks were port in the storm because they were strong and diversified. I'm not just talking about JPMorgan, there were lots of them out there who were ports in the storm and helped countries survive," Dimon said.
Tidjane Thiam, Chief Executive of insurer Prudential told delegates at the Forum that there had indeed been excesses in the financial crisis that needed to be fixed, but warned against shrinking the size of the financial industry significantly.
"There will not be any growth, the world economy will not get out of the crisis in which it is without a functioning financial sector," he said. "We all perform a very valuable social function…nobody can say what is the optimal size of the financial sector, I don't think it is a very productive debate," he said.
That view was echoed by Andrey Kostin, CEO of Russia's VTB Bank, who called for better, but not necessarily, more regulation and said we would not return to strong growth unless we have "a proper financial industry, which provides money for further economic growth."
"I'm not blaming anybody. What happened here in Davos was very important five years ago when we sat together. Bankers, regulators, governments and started to talk how to improve the situation…yes banks we took too much risk…but we took much risk because the situation was such that everyone enjoyed the life, the governments, the regulators, the bankers…the people," he said.
Dimon said JPMorgan took risks, but that it managed those risks carefully.
The bank lost $6 billion on the so-called whale trades last year but still managed to earn record profits. Dimon apologized to shareholders for the losses. He defended the bank's track record and said that it had moved on.