(Adds further quotes from Powell, analyst quote, market reaction) Oct 6 (Reuters) - The U.S. economic recovery remains far from complete and could still slip into a downward spiral if the coronavirus is not effectively controlled and growth sustained, Federal Reserve Chair Jerome Powell warned on Tuesday in a call for more help to businesses and households. “The expansion is still far from complete,” Powell said in remarks describing how even if the recovery simply slows too much it could lead to “tragic” outcomes for the less well-off, widening inequality, and a situation where “weakness feeds on weakness.” In that situation, he said, officials should risk doing too much for those that need it rather than too little, an implicit call on members of Congress and the Trump administration to aim high in their still-stalemated deliberations over how much more to spend on aid for households and businesses. Powell, who held earlier public policy jobs focused on reducing the federal deficit, said those concerns should now be set aside given the one-sided risks - more bad than good - facing the United States six months into its battle against the coronavirus pandemic and the economic fallout from it. “Too little support would lead to a weak recovery, creating unnecessary hardship for households and businesses,” Powell said in remarks delivered online to the National Association for Business Economics. “The risks of overdoing it seem, for now, to be smaller. Even if policy actions ultimately prove to be greater than needed they will not go to waste. The recovery will be stronger and move faster.” The comments mark a slight shift in Powell’s analysis of where the economy stands entering a critical phase in which the virus continues to spread while the economy divides between sectors and people doing well and those facing serious trouble. Where his earlier rhetoric focused on building a financial “bridge” to the post-pandemic era, he has now suggested that even a recovery that slips into too low a gear could devolve into a self-fulfilling recession. “The economy is recovering, but even if we don’t have an immediate double-dip recession, if it’s just a very, very slow recovery, that itself could be problematic,” said Kathy Bostjancic, chief U.S. financial economist with Oxford Economics. U.S. stocks fell after Powell’s comments. The dollar was little changed against a basket of currencies while Treasury prices were mixed. WEAKNESS FEEDING ON WEAKNESS Powell did not mention any further Fed programs that are being contemplated beyond the roughly dozen rolled out in the spring, many still largely untapped and putting potentially trillions of dollars at the disposal of firms and credit markets. However members of Congress and the Trump administration are negotiating over further fiscal programs of perhaps $2 trillion or more, efforts that many at the Fed and elsewhere feel is vital at this stage in the U.S. recovery. So far, Powell noted, the worst has been avoided, largely because of the quick action by officials last spring. Government loans to small business and enhanced unemployment benefits have “supported a strong but incomplete recovery in demand and have - for now - substantially muted the normal recessionary dynamics that occur in a downturn,” with fewer bankruptcies and fewer permanent layoffs than would have occurred otherwise, he said. But despite some bright spots like a turn upward in business investment, Powell said the pace of improvement “has moderated,” with slower job growth and “notable” layoff announcements from large companies. There is, he said, a “risk that the rapid initial gains from reopening may transition to a longer-than-expected slog back to full recovery.” That sort of prolonged slowing, he warned could “trigger typical recessionary dynamics as weakness feeds on weakness.” (Reporting by Howard Schneider and Ann Saphir; Editing by Andrea Ricci)