The yen has fallen after Prime Minister Yoshihiko Noda of Japan said he was set to dissolve parliament and hold a snap election.
It fell to 80.83 yen against the US dollar, its lowest level for 6½ months.
The BBC reports there is no guarantee the government would win an election and opposition leader Shinzo Abe has called for aggressive monetary easing by the central bank.
Mr Abe has said the bank should print "unlimited yen" to help fight deflation. But analysts said such a move would weaken the yen even further.
A formal announcement of the election date is expected on Friday.