U. S. Federal Reserve Chairman Ben Bernanke on Friday expressed a grave concern over the stagnation in the labour market, but didn't provide a clear signal about whether the central bank would launch a fresh round of monetary easing.

Speaking at the Kansas City Fed's annual Jackson Hole conference, Bernanke said that the labour market was far from satisfactory, and assured the Fed was ready to take more action to help the struggling economy.

He added that the Fed would have to weigh the potential costs and the benefits of more monetary easing through bond purchases. But he also hinted that the costs of further monetary easing would likely be worthwhile.

Speaking on the topic he added, "As we assess the benefits and costs of alternative policy approaches ... we must not lose sight of the daunting economic challenges that confront our nation."

He underlined that the central bank would provide more policy adjustments if required to encourage a stronger economic recovery and sustained improvement in labor market conditions.

The positive statement from the Federal Reserve chairman provided a much needed boost to stock markets. The Dow Jones industrial average gained 90.13 points or 0.69 per cent to close at 13,090.84.

The Standard & Poor's 500-stock index and the NASDAQ composite index jumped 0.51 per cent and 0.60 per cent to close at 1,406.58 and 3,066.96 respectively.