The Australian government says it is closely monitoring Indonesia's investigation into events surrounding the deaths of two people protesting against the activities of an Australian-owned mining company in Sumbawa on Christmas Eve. Arc Exploration halted its gold exploration activities on Wednesday.

Acting Prime Minister Wayne Swan said on Thursday that the government was "quite concerned" about the events at Sape port. "The Indonesia authorities are investigating what's gone on... and let's look at what they've got to say following their investigation," he was quoted by the Australian Associated Press as saying.

Christine Milne from the Australian Greens Party called on the government to determine whether Arc have, or have ever had, a "paid relationships with Indonesian police or military for onsite security."

"Up to now, the Australian government has turned a blind eye to payments to police and military by Australian mining companies in Indonesia, treating it as the cost of doing business," she was quoted by AAP as saying.

Arc denied any involvement in the protests. "Arc's activities and staff have no connection with the port of Sape, and any suggestion that Arc was involved with Saturday's events at Sape is incorrect," Arc said.

Arc issued a statement on Wednesday saying its activities were limited to exploration work. "The objective of this exploration work is to better understand the geology and mineral potential of the area, which currently is undefined," Arc said. "There is no gold mine existing or under construction, nor is any gold mine presently contemplated."