Asia shares inched ahead while the dollar slipped on Tuesday as a dearth of major data left markets with little to do but second guess whether the Federal Reserve will raise U.S. interest rates this year.

MSCI's broadest index of Asia-Pacific shares outside Japan edged up 0.2 percent, with South Korea and Australia adding similar amounts.

Japan's Nikkei went the other way and eased 0.4 percent as the yen gained on the dollar.

The whole world seems to have hushed ahead of comments from Fed Chair Janet Yellen at the central bank's annual meeting in Jackson Hole on Friday. Investors still doubt the stars will align for a hike anytime soon, so a hawkish tone from Yellen would challenge that equanimity.

"Ever so slowly, the market does seem to be reluctantly acknowledging the chorus of senior Fed speakers who have suggested recently that a 2016 rate hike is still quite probable and September is 'live'," wrote analysts at ANZ in a note.

"But in reality, the response has been very muted."

Indeed, U.S. Treasuries actually rallied on Monday, with 10-year yields at 1.55 percent after falling 4 basis points overnight.

Fed fund futures imply around a 24 percent chance of an easing in September, rising to around 50 percent by December. A quarter-point hike is not fully priced in until September next year.

On Wall Street, the Dow ended Monday down 0.12 percent, while the S&P 500 lost 0.06 percent and the Nasdaq added 0.12 percent.

Biotech stocks received a boost from Pfizer's $14 billion acquisition of cancer drug maker Medivation, which jumped nearly 20 percent.

Of the 479 companies in the S&P 500 that have reported earnings, 71 percent have topped expectations, according to Thomson Reuters data. Earnings are currently showing a decline of 2.3 percent for the quarter.

In forex markets, the dollar slipped a touch to 94.442 against a basket of currencies. The index fell about 1.3 percent last week on what traders perceived as mixed signals from Fed officials.

The dollar drifted down to 100.11 yen from 100.30 late in New York, while the euro nudged up to $1.1331.

The New Zealand dollar blipped higher after the country's central bank forecast another 35 basis points in possible rate cuts, less than many investors had wagered on.

The kiwi dollar rose around a third of a cent to $0.7310 in reaction.

Oil remained under pressure after shedding 3 percent on Monday. Prices retreated from two-month highs on worries about burgeoning Chinese fuel exports, more Iraqi and Nigerian crude shipments and a rising U.S. oil rig count.