Japanese manufacturers' sentiment turned positive in the three months to June for the first time in nearly two years, a closely-watched central bank survey is likely to show on Monday in a sign recent market turbulence has yet to hurt the feel-good mood created by the government's reflationary policies.

The Bank of Japan's "tankan" survey will likely show the headline index for big manufacturers' sentiment improved 11 points from three months ago to plus 3, according to a Reuters poll.

That would be the second straight quarter of improvement and the first positive reading - which means optimists outnumbered pessimists - since the survey of September 2011, and vindication of Prime Minister Shinzo Abe's "Abenomics" policy of aggressive monetary stimulus and fiscal spending.

Service-sector sentiment also likely brightened as consumers spent more, with the index for big non-manufacturing companies likely to have risen 5 points to plus 11, the Reuters poll showed.

A positive reading will bode well for the central bank, keen to end grinding deflation that has haunted Japan for 15 years and achieve its 2 percent inflation target in roughly two years through aggressive monetary stimulus.

"You cannot deny that the economy is improving, and that domestic demand is leading the way," said Hiroshi Miyazaki, senior economist at Mitsubishi UFJ Morgan Stanley Securities in Tokyo.

"Government stimulus spending is contributing to growth and the services sector is gaining strength. The BOJ's monetary easing is becoming more effective, so there's no need for additional measures."

The upbeat survey was compiled amid the market turmoil that drove up bond yields and wiped out gains in Tokyo shares made on hopes for Abe's stimulus plans. It should reinforce views the world's third-largest economy is steadily recovering, analysts say.

Big manufacturers and non-manufacturers both expect business conditions to improve further three months ahead, a sign they see the negative effect of the recent market turbulence on the economy as limited at least for now, the poll showed.

Positive market sentiment turned around in late May when the BOJ's huge asset purchases disrupted the bond market and drove up yields which, coupled with expectations of the U.S. Federal Reserve's tapering of monetary stimulus, hit global stocks and triggered a rebound in the safe-haven yen.

Still, the tankan report, a key touchstone for BOJ policymakers, will likely reinforce the view that Japan's economy remains on track for a steady recovery backed by a pickup in exports and private consumption.

The tankan's sentiment indexes are derived by subtracting the percentage of respondents who say conditions are poor from those who say they are good.

Big firms are likely to increase capital expenditure by 2.9 percent in the current business year from April, the Reuters poll showed, a sign the positive mood may be prompting them to expand business operations.