Border crossings between Indonesia and Papua New Guinea that were closed last month remain restricted due to the security situation in Papua province, a military official said on Tuesday.

Air Vice Marshal Sagom Tamboen said the closure, originally aimed at boosting security for the July 8 election, had remained in place due to several shooting incidents and other violence in the vicinity of the PT Freeport Indonesia mining area near Timika.

Both countries had agreed to keep the borders closed indefinitely in anticipation of any further violence in the province.

"The closure is to anticipate the impact of the incidents, including the possibility of foreign interference in the area," Sagom said.

The Freeport incidents began on July 8 when a company bus and security post were set on fire early in the morning.

Three days later, an Australian employee of Freeport was shot dead by unknown gunmen on the access road to the mine site.

The following day, an Indonesian security officer employed by Freeport was also shot dead by unknown gunmen along the same road.

A day later, a Papuan police officer was found dead with serious wounds caused while reportedly fleeing from an ambush.