$A higher but US debt crisis concerns remain

The Australian dollar was trading higher this morning, but traders remain wary of the unresolved debt crisis in the US.

At 0700 AEST, the Australian dollar was trading at 108.44 US cents, up from 108.13 US cents yesterday.

Since 1700 AEST yesterday, the local unit traded between 107.90 US cents and 108.77 US cents.

Republicans and Democrats presented competing plans overnight to alleviate the country's debt ceiling crisis and to avoid an August 2 default.

House of Representatives Speaker John Boehner unveiled the Republican plan that would raise the borrowing limit by $US1 trillion ($A926.7 billion) through year's end, while the Democrats proposed to raise the debt limit by $US2.4 trillion ($A2.22 trillion).

GFT Forex director of currency research Kathy Lien said the stalemate was making currency traders nervous and prevented the Australian dollar from extending its gains.

"I think the lack of clarity... is really keeping traders on the sidelines and that's what we're seeing in the price action in the markets," Ms Lien said.

The US dollar slid against the Swiss franc and the Japanese yen overnight. It fell to a record low of 0.8018 Swiss franc, later inching up to 0.8057.

Ms Lien said the movement suggested that the Swiss franc and the yen were seen as the only safe-haven currencies remaining on the market.

"The double-troubles in Europe and the US is making the Swiss franc the darling of the currency market right now.

"As long as the swiss franc continues to rise, it shows us that investors remain nervous."

Reserve Bank of Australia governor Glenn Stevens is due to address a charity event in Sydney tomorrow on economic policy.

"That could weigh on the Australian dollar, simply because we haven't seen much hawkishness from the RBA, but aside from that, I don't expect major movement," Ms Lien said.