The Group of 20 (G20) major advanced and emerging economies are calling for "all countries and jurisdictions" to meet global standards for financial and tax transparency by mid-2017.
The G20 called for "objective criteria" for identifying "non-cooperative jurisdictions," in a joint statement issued Friday in Washington on the sidelines of the spring meetings of the World Bank and International Monetary Fund.
"Defensive measures will be considered by G20 members against non-cooperative jurisdictions if progress ... is not made," G20 finance ministers and central bank chiefs said in their communique.
The G20 said that increased transparency about the owners who benefit from shell companies and similar entities "is vital to protect the integrity of the international financial system, and to prevent misuse of these entities and arrangements for corruption, tax evasion, terrorist financing and money laundering."
Following this month's "Panama Papers" revelations about the use of shell companies to conceal assets in tax havens, G20 countries vowed to "lead by example" in improving information sharing about ownership arrangements "between competent authorities for the purposes of tackling tax evasion" and other illicit transactions.
The G20 statement echoed a proposal this week by the European Union's five largest economies for prompt action to increase transparency about foreign tax havens. Germany along with Britain, France, Italy and Spain - the so-called G5 - said they were quickly launching a pilot project for sharing information about companies founded in tax havens.
Earlier Friday, German Finance Minister Wolfgang Schaeuble said that such proposals are not a "100-per-cent solution" but could narrow the gaps exploited by people seeking to evade taxes or hide ill-gotten gains.
Reporting about a massive data leak from Panama-based law firm Mossack Fonseca detailed how money was funnelled to shell companies in tax havens. The exposure ratcheted up pressure on Panama, where the banking system has long catered to foreign depositors.
Panamanian authorities seized computer servers this week during a search of Mossack Fonseca's offices, and on Thursday the government said it would implement international transparency measures in its banking system.
"We have reiterated our full commitment to cooperating with the international community during investigations and to continue to implement significant reforms to strengthen the transparency of our financial and legal framework," said Ivan Zarak, Panamanian vice minister for economy.
Organization for Economic Co-operation and Development (OECD) Secretary-General Angel Gurria said it appeared Panama would comply with tax data-sharing standards due to take effect next year among some 90 participating countries.
The Panamanian concession shows that the international mobilization to increase financial transparency can be effective, Schaeuble said.
Iceland's prime minister resigned after his foreign accounts were exposed in the Panama Papers, and many other government officials, athletes and celebrities around the world have been named, though whether their transactions were illegal was not clear.