A lack of G20 criticism for Abe's economic policy appeared to give him a freer hand to pursue Japan's efforts to jolt its manufacturing sector.
"The lack of specificity will mean that the G20 statement will allow further unobstructed" yen weakness in the months ahead, Mitul Kotecha of Credit Agricole CIB said in a market commentary.
The dollar gained against the yen, after retreating earlier, trading up 0.44% to 93.22 yen. The euro was up 0.34% to 129.39 yen, and was unchanged against the dollar at $1.34.
Mainland Chinese shares were mixed after a weeklong break for Lunar New Year. The Shanghai Composite Index fell 0.5% to 2,421.56. Hong Kong's Hang Seng fell 0.3% to 23,381.94.
"Today there is some softening but not large selling pressure," said Linus Yip, strategist at First Shanghai Securities in Hong Kong. "The U.S. stock market will be closed, so maybe market sentiment may be a little more cautious."
Last week, the yen fell to a near three-year low against the dollar and the euro. The yen has been steadily declining since December because of expectations that Japan's central bank would take action resulting in a weakening of the yen.
Since the start of the financial crisis, central banks around the world have been trying to stimulate their economies by keeping interest rates extremely low to encourage consumers and businesses to borrow and spend. One way central banks drive down rates is to use their power to print money to buy up large quantities of bonds.
Several developing economies have recently criticized the U.S. program of quantitative easing for pushing up the value of their currencies. By buying up bonds, the U.S. Federal Reserve has also increased the amount of money in circulation. This has had the side-effect of driving down the value of the U.S. dollar relative to others.
Benchmark oil for March delivery was down 23 cents to $95.62 per barrel in electronic trading on the New York Mercantile Exchange. The contract closed at $95.86 a barrel on the Nymex on Friday.
AP Business Writer Pamela Sampson contributed from Bangkok