TOKYO (Reuters) - Japan's consumer spending kept shrinking for a 13th straight month in March, government data showed on Friday, creating challenges for policymakers seeking to engineer self-sustaining economic growth and normalise monetary policy.

Household spending fell 1.2% in March from a year earlier, the data showed, against economists' median forecast for a 2.4% drop and following a 0.5% decline in February.

On a seasonally adjusted, month-on-month basis, spending increased 1.2%, versus an estimated 0.3% contraction and a 1.4% rise in February.

Separate data from Thursday showed Japanese real wages in March shrank for two straight years, as the rising cost of living outpaced nominal wages.

Weak household consumption is a source of concern among Japanese policymakers who want to see sustained economic growth led by strong wage hikes and solid consumer spending.