The preliminary Markit/Nikkei manufacturing Purchasing Managers' Index (PMI) for Japan declined to 48.0 in April from 49.1 in March. It was the lowest level since January 2013.

A reading below 50 indicates contraction of activity, a reading above 50 indicates expansion.

The index was mainly driven by drop in output, new orders and input prices.

"Manufacturing conditions in Japan worsened at a sharper rate in April. Both production and new orders declined markedly, with total new work contracting at the fastest rate in over three years," economist at Markit, Amy Brownbill, said.