TOKYO, Aug 12 (Reuters) - Japan's biggest refiner, Eneos Holdings Inc, said on Wednesday its refineries' run rate in the April-June quarter fell to 68%, the lowest since 2010, as demand for oil products has collapsed because of the novel coronavirus pandemic.

"The utilization rate will likely remain near the current level of around 70% later this year if demand for petroleum products stays flat," Soichiro Tanaka, senior vice president at Eneos, which was formerly known as JXTG Holdings, told a news conference.

The quarterly utilization rate of crude distillation units (CDUs), excluding an impact from scheduled maintenance, plunged from 92% a year earlier to the lowest level since the formation of the former JX Nippon Oil & Energy, through a merger of Nippon Oil, Japan Energy and Nippon Petroleum Refining in 2010, a spokesman said.

Its sales of petroleum products and petrochemicals dropped 21.5% in the April-June quarter from a year earlier.

Asked whether Eneos planned to close any refineries to cope with weaker demand, Tanaka said it was still considering ways to optimize its refineries' operations, without elaborating.

The chairman of Eneos, Tsutomu Sugimori, said in May that the refiner would adjust its production facilities to reflect weakening demand.

Eneos, which accounts for about half of the market, has already decided to shut a refinery in Osaka, with partner PetroChina, and its Muroran refinery in Hokkaido.

For the April-June quarter, Eneos reported a 4.88 billion yen ($45.7 million) net loss as the slump in oil prices caused a hefty inventory loss.

For the year to March, the refiner stuck to its May forecast of a 40 billion yen net profit, against a net loss of 187.9 billion yen a year earlier. ($1 = 106.8200 yen) (Reporting by Yuka Obayashi Editing by Robert Birsel)