* MSCI Asia ex-Japan down 0.1 pct, Nikkei opens down 0.6 pct
* Yen resumes declines
Asian shares eased on Friday with investors turning cautious as weak euro zone growth data presaged the G20 meeting in this session and on Saturday in Moscow.
The MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.1 percent.
Australian shares dipped 0.1 percent as the market consolidated gains after touching a 4-1/2 year high on Thursday, compounded by the weak euro zone data and a $3 billion annual loss from global iron ore miner Rio Tinto Ltd.
South Korean shares opened up 0.1 percent after closing on Thursday at a fresh three-week high in thin trade, helped by a halt in the yen's slide.
"A short-term correction is likely as the domestic stock market recently rebounded from losses," said Lee Jae-man, an analyst at Tong Yang Securities.
The Nikkei stock average opened down 0.6 percent.
Markets in China and Taiwan remain shut for the Lunar New Year holiday.
The yen steadied after gaining on Thursday for the third straight day, adding 1.5 percent for its best three-day advance in three weeks. Investors have cut back yen short positions as speculation grew that the G20 could take exception to the yen's steady weakness over the past three months.
Many traders and analysts say currencies will be discussed, but yen weakness is unlikely to top the agenda so long as Japan explains it is pursuing strong monetary easing to reflate the economy, and yen devaluation is a side-effect.
"The prevailing sense from all of the official commentary on currencies this week is that the international community is willing to tolerate a weaker yen so long as Japan continues to focus on domestic policies and probably moderates its rhetoric on the currency," says JPMorgan in a note.
The dollar inched up 0.2 percent to 93.07 yen. It marked its highest since May 2010 of 94.465 on Monday. The euro rose 0.3 percent to 124.30 yen, after scaling its peak since April 2010 of 127.71 yen last week.
The euro steadied around $1.3359 after falling to a three-week low of $1.3315 on Thursday as a report showed the 17-nation euro zone economy shrank by 0.6 percent in the last three months of 2012. The bloc's two largest economies, Germany and France, also contracted by more than expected, dampening hopes for a recovery in early 2013.
The bleak growth outlook weighed on the euro by raising expectations the European Central Bank will cut interest rates.
The weak euro zone growth data sent European shares lower on Thursday, but U.S. stocks ended nearly flat as U.S. weekly jobless data and a $23.2 billion bid in cash by Warren Buffett's Berkshire Hathaway and private equity firm 3G Capital for ketchup and baby food maker H.J. Heinz cut losses.
Yields on U.S. Treasuries slid from 10-month highs on Thursday as investors shifted their money to assets seen as safe havens, pushing up bond prices.
With Japanese stocks rising on the yen's weakness, Japanese mutual funds saw the biggest monthly net inflow in 21 months in January as retail investors poured into money reserve funds after locking in profits from rising domestic stocks and equity funds, the Investment Trusts Association said on Thursday.
U.S. crude was steady near $97.33 a barrel.