The US dollar has proved jittery in the last 24 hours, although with a lack of data analysts are debating the significance of the movement.

Ahead of the Federal Reserve meeting the greenback fell away, although analysts professed to be perplexed by the factors at work.

Societe Generale currency strategist Niels Christensen told Bloomberg he believed there was an underlying weakness in the currency which the imminent Fed meeting had exacerbated.

"It's difficult to find any factors supporting the dollar,'' he argued.

Meanwhile, the US Treasury is expected to publish its report on China in the coming weeks, with reports suggesting China's tinkering with the yuan will be castigated in the document.