In late afternoon New York trading, the dollar was up 0.5 percent at 99.58 yen after hitting a peak of 99.68, its highest since June 5.
(Read More: Dollar to Face Stiff Resistance on Its Way Up: Chart)
Expectations the Bank of Japan will continue with aggressive monetary easing also weighed on the yen, with the euro up 0.8 percent at 129.93 yen, having earlier hit a near three-week peak of 130.11 yen.
The euro was up 0.4 percent at $1.3064, recovering after a dip last week to $1.2983, its lowest since early June. But it stayed below chart resistance at $1.3106, the 100-day moving average, and the 200-day average at $1.3074. Against the Japanese currency, it traded up 0.9 percent at 130.08 yen.
The dollar index, which measures the dollar's value against a basket of major currencies, was last down 0.2 percent at 83.013, having hit a four-week peak of 83.344 on Friday.
Friday's U.S. payrolls report will be key. A strong reading would boost the dollar by fanning speculation about an early paring-back of the Fed's $85-billion-a-month bond-buying.
An improving domestic economy should give the U.S. currency a big advantage over the euro and yen.
In contrast to the Fed, the European Central Bank is likely to emphasize at its monthly meeting on Thursday that the euro zone economy still needs help.
The Bank of England and the Reserve Bank of Australia also hold policy meetings this week.
The Australian dollar hit a three-year low of US$0.9105 before recovering to last trade at US$0.9234, up 1.1 percent. The British pound was flat at at $1.5214.