Business confidence among Japan's small firms and non-manufacturers worsened during the second quarter of the year, a central bank survey showed Friday, underscoring the slowdown in the world's number three economy.

The Bank of Japan's closely watched Tankan report also found that sentiment among major manufacturers remained stuck at its lowest level since Prime Minister Shinzo Abe kicked off his much-vaunted programme to boost growth, dubbed Abenomics, over three years ago.