Japan has said it is monitoring a rise in the value of the yen, but has declined to comment on talk that it will intervene in currency markets.
The yen hit a 15-year high against the US dollar this week - adding to worries about the impact on exporters.
Japanese authorities last intervened in the currency in March 2004.
That brought to an end a 15-month spree which saw Japan sell 35tn yen ($410.7bn; £263bn) to try to protect exports and fight deflation.
Asked if foreign exchange market intervention was one option currently being considered by the government, Finance Minister Yoshihiko Noda said: "I'll refrain from commenting."
But he added that the government would take "appropriate" action.
This included monitoring the yen and talking to other governments about the volatile, fluctuating currency and stock markets.
The US dollar hit a 15-year low of 84.72 yen on Wednesday after the US Federal Reserve said it would buy more government debt and raised concerns about the slowing global recovery.
Japan is among the world's biggest exporters - with global demand for its goods from cars and auto parts to consumer electronics and semiconductors.
A strong yen makes Japanese goods more expensive - and potentially less attractive - to overseas buyers.
It also means the profits that Japanese firms make in overseas sales are worth less when they are repatriated.
The latest data showed that while Japanese exports rose in June, it was at a slower pace than in recent months.
And analysts have warned that the impact of the strong yen is likely to become more visible later this year, saying exports to Asia are unlikely to show further growth.