The BoJ is widely expected to ramp up its bond buying and extend the maturities of the bonds it purchases under new Governor Haruhiko Kuroda at the bank's April 3-4 policy gathering.

Kuroda said he wants to combine two different schemes that the central bank uses to purchase government debt, reinforcing expectations of bold monetary stimulus.

Expectations of aggressive action from the BoJ is largely behind the dollar's whopping 7.7 percent gain against the yen so far this year, but in recent weeks investors have used its rise to cash in on gains.

"It's a bit of a give-back for the yen after its rally over the weekend, and now the market is anticipating what the BoJ would and won't do at this week's policy meeting," said Brian Dangerfield, currency strategist at RBS Securities in Stamford, Connecticut.

Traders, however, reported thin liquidity in major currencies as European markets reopened after the Easter holiday, and said price moves were expected to be subdued.

The dollar was last up 0.2 percent against the yen at 93.42 yen after earlier hitting 92.54 yen, its lowest since March 1.

If the BoJ falls short of market expectations, the yen should rally and the dollar should weaken, analysts said.

"We think there is potential for disappointment at this week's BoJ policy meeting," Credit Suisse wrote in a report.

The BoJ may reserve to implement more aggressive measures down the road, which would be a near-term negative for the dollar versus the yen.

"We nonetheless remain bullish on the pair over the medium term and would look for a correction as an occasion to build longs," the firm said.

The euro last traded flat against the yen at 119.74 yen , recovering after hitting a five-week low of 119.10 yen. Chart support for the euro was seen at its late February trough of 118.74 yen.

Gains in US stocks have also boosted the dollar. The S&P 500 stock index closed within reach of its all-time intraday high of 1,576.09 just days before US non-farm payrolls report for March due Friday.

With the state of the US labor market key to the path of US Federal Reserve policy, Friday's jobs data has the potential to sway currency market sentiment.

EURO ON THE DEFENSIVE

The euro slipped against the dollar, pressured by euro zone data showing the region was well into economic contraction territory last month.

This has prompted expectations European Central Bank President Mario Draghi would strike a more dovish tone at Thursday's monetary policy outlook meeting. He could also provide hints about a possible rate cut.

Euro zone purchasing managers' surveys showed a deepening decline in manufacturing activity in March, with Italy and Spain particularly weak.

Investors were cautious before Thursday's European Central Bank meeting. Although interest rates are expected to be left on hold, analysts saw a small chance of a cut.

"The data does ... confirm that the outlook for the euro zone has deteriorated over the last month on almost all fronts, including economic, banking sector and EMU (European Monetary Union) perspectives," said Camilla Sutton, chief currency strategist at Scotiabank in Toronto.

"We expect euro zone fundamentals to deteriorate further - this combined with outflow pressures should keep the euro's downward trend intact," she said. Sutton expects the euro to close the year at the $1.25 level.

Further weighing on the euro and its outlook was the resignation of Cyprus' finance minister after concluding a 10 billion euro bailout deal with international lenders in which the country slashed its dominant banking sector and hit depositors with losses.

The euro was last down 0.3 percent against the dollar at $1.2814, hovering within sight of a four-month low of $1.2750 hit last week, according to Reuters data.