Traders said speculators' positioning and some technical indicators suggested that rallies in the euro and the Australian dollar against the yen could pause in the short run with the latest earthquake being used by some to book profits.
"Clearly investors are pausing to re-assess the impact from the latest earthquake," said Jeremy Stretch, head of currency strategy at CIBC World Markets.
"This has put a cap on the risk-on trade we saw earlier in the session. Equity futures are off their highs and cross/yen positions are being pared back."
The euro was down 0.4 percent at 122.24 yen having hit its highest since May 2010 of 123.33 yen on trading platform EBS. The Australian dollar was down at 89.24 yen having scaled a high of 90.04 yen earlier, its highest since September 2008.
Commerzbank technical analyst Karen Jones said near-term support for the euro/yen pair lay around the 121.55/60 yen area, the lows hit in late February 2010, adding that short yen positions could see some more profit taking in the short run.
She saw near-term support for the Australian dollar at 86.40 yen, the 23.6 percent retracement of its recent rally from a low of 75.05 yen on March 17 to a high of above 90 yen on Monday.
The dollar also lost ground, and was last down 0.2 percent at 84.60, hitting a session low of 84.55 yen, according to Reuters data, soon after news of the fresh tremors in Japan.
The yen has fallen sharply in the wake of joint yen-selling intervention by the Group of Seven nations in March.
The G7 stepped in after the yen hit a record high of 76.25 yen to the dollar on March 17, propelled by speculation that Japanese investors would repatriate their overseas assets after a massive earthquake and tsunami struck Japan's northeast on March 11.
Market expectations for the Bank of Japan to lag behind other central banks in raising interest rates and a drop in volatility after the G7 intervention have shifted the focus to the appeal of carry trades, a tactic of selling low-yielding currencies to fund investment in higher-yielding ones.
SHORT YEN POSITIONS RIPE FOR PULLBACK
Data from the Commodity and Futures Trading Commission (CFTC) showed speculators went net short on the yen for the first time in six weeks and by the biggest margin since May 2010 at a net 43,231 contracts in the week to April 5.
Technical indicators such as the 14-day relative strength index and slow stochastics also suggested that the euro and Australian dollar are in overbought territory against the yen, pointing to the possibility of a near-term pull-back.
Positioning in the Australian dollar also looked stretched judging by the CFTC data, which showed that currency speculators held record long positions in the Aussie dollar in the week to April 5.
"The Aussie/yen positions are clearly overbought and ripe for a correction," said Adam Myers, senior currency strategist at Credit Agricole. "Should the U.S. dollar start to reverse course, and that trend will become clear this week, we will see some of those big carry trade positions being unwound."
For now, though, the U.S. dollar eased back in the direction of last week's 16-month low against a basket of major currencies , and also extended its recent losses against some Asian currencies.
A number of Asian central banks are said to have intervened to prevent their currencies from rising, and traders said they were likely to recycle those proceeds into the euro, lending support to the common currency.
The euro slipped 0.2 percent to $1.4460 hovering around the 21-hour moving average at $ 1.4454, with bids said to be around the $1.4410-25 area and lower. It had hit a 15-month high of $1.4489 on Friday.