A land mine exploded accidently during clearance training at a military base in western Cambodia on Thursday, killing two people, including an Australian trainer, and injuring three others, police said.

National police said the explosion occurred in Kampong Speu province when a soldier who was being trained mishandled a decades-old land mine that had been removed from the ground. They said a 45-year-old Australian trainer was killed and another 41-year-old Australian was wounded.

Police said one Cambodian soldier was killed and two others were injured.

Some 60,000 Cambodians have been killed or wounded by mines since they were first deployed in large numbers in 1979, when the genocidal Khmer Rouge regime was ousted from power and began 18 years of guerrilla warfare.

Prime Minister Hun Sen said last year that land mines continue to kill or maim nearly 100 people per year, and the country needs more than $400 million in aid to remove all of them by 2025.

Cambodia has cleared about 1,500 square kilometers (580 square miles) of mines, but nearly 2,000 square kilometers (770 square miles) of land remains littered with the munitions, Hun Sen said.