Japan's consumer prices were expected to fall in June for the fourth straight month, a Reuters poll found, keeping alive market expectations the central bank will expand an already massive stimulus program to hit its 2 percent price goal.

Separate data next week is also expected to show exports slumped in June from a year earlier, a sign the economy is suffering from the hit from a strong yen and global uncertainties after Britain's vote to leave the European Union.

The core consumer price index (CPI), which includes oil products but excludes volatile fresh food prices, was expected to have fallen 0.4 percent in June from a year earlier, the poll of 21 economists found. This follows a 0.4 percent annual fall in May.