Bob Diamond, head of Barclays Capital, said: "This is a time when isolated actions in the US and the UK are not beneficial. There is the opportunity to work constructively through the G20."
In response to the US president Barack Obama's initiative to restrict the size of banks, Mr Diamond said: "They [the big banks] fulfilled an important function in helping governments and corporates to transfer risk, particularly across borders."
"It's very important to step back and be very thoughtful about the role of trading and the role of risk in banks, because without risk we don't have a banking industry. Banks willing to take cross border risks are essential to have jobs and economic growth."
He also criticized the UK's move to tax bankers' bonuses and warned that these nations could shift their focus on domestic policy and elections.
Charles Dallara, head of the Institute for International Finance, a lobby group for big global banks, said: "While we respect the right of any government to propose whatever measures it may deem needed in its market, it's not going to be effective at all to have one set of rules in the US and one in Europe and one in the UK and one in Japan and one in Canada."
Joseph Ackerman, CEO of Deutsche Bank, said: "We are in a global financial market and we need a level playing-field. It would not be productive to have different regulatory frameworks."
Jaime Caruana, head of the Bank for International Settlement, which coordinates regulations in the fields of financial services to promote international financial stability, also acknowledged the need of international cooperation to devise new rules for banks.
However, Michael Geoghegan, CEO of HSBC Holdings, said: "What's been mentioned by President Obama and has come out already in the UK from the FSA (Financial Services Authority) are discussions, documents. I would suspect when they actually become regulations they will be slightly different."