Yen extends losing streak as traders question BOJ's rate-hike pace

The currency has also come under pressure because the Federal Reserve and other global central banks have increased rates and markets price in further hikes this year.

Taken together, the developments illustrate that multiple forces are pressuring the yen, making traders quick to seize any opportunity to sell the currency even as officials signal support.

"Japan may step in again, but intervention is a warning shot, not a cure. Traders do not believe the tightening cycle will move fast enough to challenge the dollar's yield advantage," said Hassan Fawaz, chairman and founder of brokerage firm GivTrade.

Markets price about a 30% chance that the BOJ hikes its benchmark short-term rate to 1.5% in October and a roughly 53% chance that the Fed will lift its funds rate window by 25 basis points to 4% to 4.25%.