Major share markets extended their weaknesses for a second session, turning to losses on the week, as confidence flagged in the European Union's ability to resolve the crisis before it inflicts further damage on the global economy.
The Nikkei dropped 1.5 percent to 8,536.46, losing 1.2 percent for the week after logging a weekly gain of almost 6 percent last week. It slipped below its 75-day moving average of 8,633 and briefly broke below another major support at its 25-day moving average, now 8,523.
A break there could open the way for a test of 8,500, a 38.2 percent retracement of its rally to a four-week high that started in later November, and 8,430, a 50 percent retracement of that rally.
The broader Topix index shed 0.9 percent to 738.12.
Singapore's Straits Times Index dropped 1.2 percent, Malaysia's benchmark index slid 0.9 percent, Jakarta's Composite Index eased 0.6 percent and the Philippine main index lost 0.5 percent, all falling to around one-week lows.
Thailand's benchmark SET index was down 0.9 percent. The Thai market is shut on Monday for a public holiday, reopening on Tuesday.
Vietnam's Ho Chi Minh Stock Exchange index fell for a fourth session, down 1.2 percent at its lowest in more than two weeks. The emerging Asian region snapped last week's gains, led by a 2.5 percent weekly loss for Singapore, which is seen as one of the most exposed economies in the regional to external shocks.
The brunt of selling in Singapore this week, however, was largely fueled by domestic stresses, after the government announced fresh steps on Wednesday to cool the property market.
A key real estate sub-index fell twice as much on the week as the main index. Leading developers CapitaLand Ltd and Keppel Land Ltd both tumbled nearly 3 percent on Friday alone.
Bangkok-based Capital Nomura Securities strategist Chai Chirasevenupraphund said developments in the euro zone debt crisis would strongly influence Thai market sentiment in coming sessions.
It's still a trading market for Thai stocks. We see some corrections in big caps because of mild selling by foreign funds after their recent buying, he said.
Baring Asset Management expects markets to remain volatile next, depending on how policymakers in Europe and the United States behave.
Hong Kong-based SooHai Lim, an investment manager at the $326 million Baring ASEAN Frontiers Fund, is overweight on Indonesia and Thailand, saying their resilient domestic economies that should weather the external slowdown. Elsewhere in regional markets, Indonesian coal miner PT Garda Tujuh Buana Tbk jumped as much as 24 percent onFriday after the Jakarta stock exchange lifted a month-long suspension on the stock.
The Philippines reported net foreign buying of $30 million on Friday, on top of $124 million of the last seven days, Thomson Reuters data showed.
The MSCI's broadest index of Asia Pacific shares outside Japan slid 2.7 percent while the MSCI's worldindex was off 0.6 percent, by 0822 GMT.
(Additional reporting by Mari Saito and Singapore bureau.)