PARIS (AFP) - China became on Tuesday the last of the G20 nations to sign up to an international pact to help crack down on tax evasion by stepping up the automatic data exchange, the OECD said.

The Group of 20 advanced and emerging nations pledged two years ago to sign up the pact as they stepped up efforts amid the global crisis to recover billions in funds that slip into offshore tax havens each year.

"Today's signing is both timely and important as the G20 has endorsed automatic exchange of information as the new global standard," OECD chief Angel Gurria said in a statement.

The Organisation for Economic Cooperation and Development, a policy forum for 34 democracies, said 56 countries had now signed up to the Mutual Administrative Assistance in Tax Matters, which provides a framework for states to automatically transfer data.

Tax evasion and tax avoidance strategies employed by multinationals are expected to be among the top issues discussed by G20 leaders when they meet next week in the Russian city of Saint Petersburg.