The benchmark Nikkei 225 index was down 0.62 percent or 132.64 points at 21,336.54 in early trade, while the broader Topix index was down 0.59 percent or 9.31 points, at 1,558.10.

"The upper house election this weekend ended with a ruling bloc victory with a majority of seats... in line with expectations, and its impact on the stock market will be neutral," Okasan Online Securities said in a commentary.

"As corporate earnings season starts this week... investors' eyes will shift away from expectations for excessive money flows to negative factors such as the worsening of corporate performances," it said.

This week, companies such as Canon and Nissan will announce earings reports while there will be a series of macroeconomic data and events, including US GDP due on Friday and the ECB meeting on Thursday.

"Stock markets globally may fluctuate as major events are scheduled to take place this week," Hirokazu Kabeya, chief global strategist at Daiwa Securities, said in a commentary.

The dollar fetched 107.76 yen in early Asia trade, from 107.72 yen in New York.

In Tokyo, some blue-chip exporters were lower, with Sony trading down 0.58 percent or 5,804 yen, Canon down 0.90 percent at 3,064 yen and Sharp down 0.43 percent at 1,3783 yen.

Asahi Group Holdings dropped 5.73 percent to 4,749 yen after the world's leading brewer Anheuser-Busch InBev said Friday it is selling its assets in Australia for 16 billion Australian dollars (US$11.3 billion) to Asahi.

On Wall Street, the Dow ended down 0.3 percent at 27,154.20.