WASHINGTON (REUTERS) - United States (US) Treasury Secretary Jack Lew warned his partners in the Group of 20 on Wednesday against the perils of "beggar thy neighbour" currency devaluations, picking out China for special mention on the eve of a G20 meeting here on global growth.

Mr Lew also underlined the importance of stronger demand in Europe for the world economy, keeping up Washington's coded pressure on Germany to loosen policies to provide more support to weaker euro zone members in the bloc's south.

"We will continue to press G-20 countries to avoid a downward spiral of 'beggar thy neighbor' policies," Mr Lew said in prepared remarks. "It is imperative that all G-20 countries follow through on their recent commitment not to target exchange rates for competitive purposes," he told an audience at Johns Hopkins University School of Advanced International Studies.

G20 finance ministers and central bankers are expected to confirm a February pledge to avoid competitive devaluations at their gathering here on Thursday and Friday, on the sidelines of the annual spring meetings of the International Monetary Fund and World Bank.