Asian shares eked out cautious gains on Wednesday as concerns about corporate earnings hobbled Wall Street while investors counted down to the European Central Bank's policy meeting later in the week.

MSCI's broadest index of Asia-Pacific shares outside Japan was a fraction firmer. Japan's Nikkei added 0.8 per cent, while South Korea's KOSPI rose 0.6 per cent.

There was more evidence of the problems plaguing Asian trade flows with Japanese exports growing at the slowest pace since mid-2014, mainly due to weakness in China.

Wall Street offered little in the way of a lead with the Dow ending Tuesday 0.1 per cent lower, while the S&P 500 eased 0.14 per cent and the Nasdaq 0.5 per cent.

The S&P healthcare sector shed 1.5 per cent, dragged by Allergan and Pfizer, while a drop in IBM offset gains in companies that reported strong quarterly results such as Verizon and United Technologies.

Earnings for S&P 500 companies are expected to have fallen about 4 per cent in the third quarter, while revenue is expected to have declined 3.8 per cent, according to Thomson Reuters data.

Economic news from the United States was moderately upbeat as housing starts increased 6.5 per cent in September to an annual pace of 1.21 million units, beating expectations for 1.15 million units.

There was also better news on bank lending in the euro zone as data from the ECB showed a further easing in credit conditions and improving demand for loans.

That might lessen the need for the ECB to immediately ramp up its 1 trillion euro asset purchase program.

The ECB's governing council meets on Thursday and markets expect it to highlight a willingness to act to boost inflation, but not just yet.

"The general consensus is that the ECB has been trying to moderate expectations this week, suggesting it's too early for discussion around extending the current QE programme," said analysts at Citi.

The euro was a whisker higher at $1.1359, but still hemmed in by support at $1.3300 and resistance around $1.1386. The dollar index, which measures the greenback against a basket of six major currencies, was last down 0.1 per cent at 94.855 .

The New Zealand dollar hit a one-week low of $0.6737 after a disappointing global dairy auction saw prices for the country's single largest export fall 3.1 per cent.

Oil prices softened on speculation US inventory data would only underline the extent of oversupply in the world. The US Energy Information Administration (EIA) will report official inventory data on Wednesday.

US crude slipped 32 cents to $45.97 per barrel, while Brent lost 18 cents to $48.53. – Reuters