The Bank of Japan, which had hoped to hold fire at least until October, is expected to scrutinise market developments, particularly yen moves, in deciding whether to expand monetary stimulus at its meeting next week.
Finance Minister Jun Azumi repeated his warning to markets against pushing up the yen too much, saying that Tokyo will take decisive action in the currency market if necessary and won't rule out any measures - a thinly-veiled threat of currency intervention.
"Recent one-sided yen gains clearly do not reflect Japan's economic fundamentals," Azumi told a news conference on Friday.
The dollar traded around 77.60 yen on Friday, having fallen as low as 77.13 yen on trading platform EBS the previous day after the Fed move, its lowest since early February.
Azumi and Economics Minister Motohisa Furukawa also expressed hope that the BOJ would take action to support the fragile economy, which is faced with growing headwinds including the stubbornly strong yen and slowing global demand.
"Overseas developments must be taken into account in guiding economic policy, including monetary policy," Furukawa told a news conference, when asked whether the BOJ should follow the Fed's footsteps and expand monetary stimulus next week.
Earlier on Friday, the government cut its assessment of the economy for the second straight month and warned that growth is pausing, signalling growing concern over the pain from the global slowdown and keeping the central bank under pressure to provide further monetary stimulus.
Many market players had expected the BOJ to hold off on expanding stimulus at its meeting next week, although the Fed's aggressive action adds pressure on the Japanese central bank to follow suit with similarly bold steps.
In a significant shift in monetary policy, the Fed said it will buy $40 billion of mortgage debt per month and will continue to purchase those and other assets until the outlook for jobs shows marked improvement.