Japan’s base oils output fell in April in the face of plant maintenance work and slower domestic demand.

Supply still rose as a share of Japan’s total refined products output amid increasingly firm base oils margins and weaker diesel values relative to crude.

Base oils output of 210,060 kilolitres (186,070t) in April fell from 231,840kl the previous month and by 16pc from year-earlier levels, government data showed.

The year-on-year fall was the first in fourteen months and coincided with the expected start of planned plant maintenance work during the month of April.

Output is likely to slip further in May and June because of additional maintenance work.

Base oils production accounted for 1.83pc of Japan’s total oil products output in April. The share rose from 1.79pc the previous month to the highest in seven months.