Indonesian police are considering using a new study which blames a "mud volcano" on bungled gas drilling as evidence in a criminal investigation into the disaster, a spokesman said Thursday.

A study by foreign scientists released this week found the mud volcano in East Java province, which started flowing in 2006, was caused by drilling by oil and gas firm Lapindo Brantas, not an earthquake as argued by the company.

"We have not yet obtained a copy of the report, but certainly we will study the report and see whether it can support the investigation we are conducting into this case," East Java police spokeswoman Puji Astuti told AFP.

The mudflow in Sidoarjo district began spewing in May 2006, swamping villages with as much as 53 Olympic swimming pools of hot mud a day.

Lapindo, which is owned by the family of Indonesia's top welfare minister and richest man, Aburizal Bakrie, has long blamed the disaster on an earthquake two days earlier 250 kilometres (160 miles) away in the city of Yogyakarta.

But the new study published in peer-assessed academic journal Earth and Planetary Science Letters concluded with "99 percent" certainty that Lapindo's drilling caused the mudflow.

The lead author of the study was British professor Richard Davies, of Durham University in northeastern England. Indonesian, Australian and US investigators also contributed to the study.

Lapindo vice president Yuniwati Teryana rejected the study, saying another "team of independent experts" had found its conclusions "wrong."

"If the data structure used is faulty, then the result of the analysis would be faulty too," Teryana told a press conference held to present the company's version of events.

She said the company was prepared to take part in a scientific debate to prove its case.

Police in East Java have struggled to put together a dossier of evidence thick enough to indict 13 mid-level executives and field workers from Lapindo and subcontractors for negligence over the disaster.

The province's prosecutor's office in February rejected the police indictment request for a third time, citing a lack of supporting evidence.

Twelve villages have been affected by the spreading mud and at least 36,000 people have been forced to flee their homes.