SYDNEY, May 7 (Reuters) - Interest rates in the United States could stay low for as long as the labour market remains weak, Janet Yellen, President of the Federal Reserve Bank of San Francisco, said on Thursday.

Yellen, a voting member of the Federal Open Market Committee in 2009, said the Fed funds rate will be low for a long time and the U.S. will have budget deficits for a lengthy period. (Reporting by Koh Gui Qing)