TOKYO - Japan's biggest refiner, Nippon Oil Corp, plans to refine 4 percent less crude in June from a year ago, a company executive said on Friday, as domestic demand for oil products remains sluggish.

Oil sales in Japan, the world's third-biggest oil consuming

nation, are down as the population ages, homeowners, business

and drivers shifts towards greener energy, and the economy

wallows in its worst recession since World War Two.

The oil firm plans to refine 3.06 million kilolitres (642,000 barrels per day) in June, 140,000 kl less than last year, and a 24 percent decline from two years ago.

Last June, Nippon Oil faced a heavier planned maintenance

schedule.

Its May crude refining volume for domestic demand was

estimated at 3.86 million kl, down 6 percent from a year earlier

and unchanged from its original plan, Masahito Nakamura, the

company's senior vice president, told reporters.

Nippon Oil, which plans to merge with smaller refiner Nippon

Mining Holdings Inc (5016.T) in April 2010, has a crude refining

capacity of 1.317 million barrels per day, more than a quarter

of Japan's total crude refining capacity.

May demand for fuel oil by nine Japanese utilities was seen

down 60 percent from a year earlier at 390,000 kl, the company

estimated.

In May, the refiner bought 20,000 kl of middle distillates

from the domestic market and its exports totalled 540,000 kl of

middle distillates and fuel oil to Asia.

Following is a table of Nippon Oil's estimated production

for May and plans for June (volumes in kilolitres, with changes

from same month a year earlier in brackets):

Production May June

Gasoline 1.19 mln ( -10,000 kl) 1.11 mln (+210,000 kl)

Middle Dist. 2.02 mln (-160,000 kl) 1.67 mln (-120,000 kl)

C-fuel oil 0.64 mln (-250,000 kl) 0.49 mln (-230,000 kl)

(Reporting by James Topham, editing by Anthony Barker)

Japan