The upstream business unit of the state-owned oil and gas firm PT Pertamina, Pertamina EP, lost 59, 000 barrels of crude oil in June due to thievery in Sumatra island, the Jakarta Post reported on Tuesday.

"We are very concerned (with the situation) because law enforcers have yet to respond to our report regarding the pillaging and the thievery," Pertamina EP spokesman Agus Amperianto said on Monday.

The report said the thieves siphoned off the oil by drilling holes in the pipeline in Jambi and South Sumatra provinces.

There were around 235 cases of similar thefts recorded across the nation this year.

Pertamina EP operates the Tempino-Plaju pipeline, which stretches from Jambi to South Sumatra delivering as much as 330, 000 barrels of oil per month.

The company estimated that its total losses from the pipeline had reached 100,000 barrels of crude oil with an estimated value between 90 billion rupiah (some $9.5 million) and 100 billion rupiah (about $1.056 billion).

The losses at Tempino-Plaju pipeline, which have been increasing month by month, proved that the law enforcers haven't done their jobs, he said.

Agus added that the crimes had also caused damage or even losses to the company's assets. Agus said the company feared the crimes would lead to fires or environmental damage.

Pertamina EP, a subsidiary of Pertamina, operates across areas totaling approximately 140,000 square kilometers. Its core business is the exploration and exploitation of oil and gas across the archipelago, which is divided to three regions: Sumatra, Java and eastern Indonesia.