Asian shares kicked off the week mostly higher after a historic deal over Iran's nuclear program bolstered risk appetite, sending the yen sharply lower against major counterparts.
A strong finish on Wall Street last week also underpinned gains. The S&P 500 recorded its first close above 1,800 and the Dow posted its longest weekly-winning streak in nearly three years, as worries about the Federal Reserve curbing stimulus in December receded.
"While there aren't any major [economic] releases in Asia today, the favorable risk mood seems enough to keep driving yen weakness. Perhaps the Iran nuclear deal, effectively setting limits to Iran's nuclear program, has added to the buoyant risk mood as it is the only fresh major development from Friday's trade," said Stan Shamu, market strategist at IG.
(Read more: This week, watch Japan data blitz and India GDP)
Iran in focus
Brent crude lost 2.6 percent in Asian trade, it's lowest level in three weeks, after Tehran vowed to curb nuclear activities in exchange for sanctions relief during negotiations in Geneva early on Sunday.
(Read more: Brent eyes $105 as Iran deal eases supply risks)
Nikkei adds 1.5%
Japan's benchmark Nikkei index closed at a new six-month peak for a third straight session, moving closer to a five-and-a-half-year high of 15,942, last touched in May.
A weaker currency propped up blue-chip exporters. The yen hit a new four-year low against the euro and a six-month trough against the U.S. dollar after Bank of Japan chief Haruhiko Kuroda said the central bank could expand its massive stimulus program if needed.
Among the top winners, electronic products makers Mitsumi Electric and Pioneer added 10 and 7 percent, respectively. SoftBank soared over 5 percent to a new thirteen-year high for a second session after hedge fund manager Daniel Loeb revealed a $1 billion-plus stake in the firm last week.
Index heavyweight Fast Retailing rose 2.4 percent amid reports that the Uniqlo clothing store operator could plan a secondary listing in Hong Kong.
Shanghai 0.5% lower
Mainland shares underperformed the broader Asian region in choppy trade. For the week ending Friday, the Shanghai Composite was Asia's best-performing index with gains of 3 percent.
Sinopec tumbled 4 percent after the government launched a safety investigation at oil and gas pipelines following an explosion at a Qingdao pipeline last week, which was reported to be the firm's deadliest known accident. Rival Petrochina eased 1.5 percent.
Defense plays outperformed with Aerospace Communication up 5.3 percent and Hafei Aviation 1.3 percent higher after Beijing declared a set of disputed islands in the East China Sea as a new air defense zone. The islands are at the heart of a territorial dispute with Tokyo and the move triggered warnings from both Japan and the U.S.
Sydney up 0.3%
Trade in Australia's benchmark S&P ASX 200 was subdued with a lack of major catalysts but a weaker currency managed to keep the index in positive territory.
The Australian dollar hit a new two-and-a-half-month low against the greenback at $0.9130 in late afternoon trade. A declining currency shores up the earnings power of miners and other firms that have significant overseas exposure.
Financials lent support with investment bank Macquarie leading gains by 1 percent.
Warrnambool Cheese rose 2 percent after announcing that it had endorsed a sweetened takeover bid from Canadian firm Saputo.
Kospi rallies 0.5%
South Korean shares pared gains after climbing to a one-week high earlier in the session. Still, sentiment rose after data showed foreign investors continued to buy local stocks, snapping a two-day selling streak.
Emerging markets mixed
Philippine shares lost 1.3 percent after JPMorgan cut the nation's 2013 growth forecast to 6.9 percent from 7.1 percent. The benchmark PSE Composite has lost 8 percent in the past month.
Indian shares however, tracked Asia-wide gains to rally 1.8 percent.
— By CNBC.com's Nyshka Chandran. Follow her on Twitter @NyshkaCNBC