"A very significant upside surprise may be positive for the dollar as it would confirm positive growth," Chow said. "The dollar, however, may slightly weaken should the number fall within the wide range of expectations."
The dollar index, which measures its value against a basket of six major currencies, earlier hit its lowest since the end of February at 81.598.
The euro rose as high as $1.3185, the strongest since April 17, after breaking above resistance around the London session high of $1.3120, according to Reuters data. It last traded at $1.3166, up 0.5 percent on the day, with traders citing buying by a German bank.
On the month, the euro rose about 2.8 percent against the dollar, its first monthly gain since January.
Inflation in the euro zone hit a three-year low and unemployment rose to a record high, data showed on Tuesday. Adding to worries, German retail sales unexpectedly fell in March while Spain's economy shrank for the seventh straight quarter in the first three months of the year.
Some analysts said that while a rate cut could see the euro initially fall, announcing further easing measures would be interpreted as a positive move by the central bank and this could lend the euro support.
A drop in U.S. government bond yields, which move inversely to price, has weighed on the dollar versus the yen. The yield differential between U.S. Treasuries and Japanese government bonds is a key driver of the currency pair.
The dollar last traded down 0.4 percent to 97.41 yen, having hit as low as 97.01 yen, the weakest since April 16. In April, the dollar rose about 3.4 percent against the yen, the largest monthly gain since January.
The Bank of Japan this month announced an aggressive plan of bond buying that entails buying $1.4 trillion in government bonds in less than two years.
While the dollar reached as high as 99.94 yen on April 11, there is an abundance of options barriers preventing it from hitting the key psychological and technical 100 mark.