Vietnam's famed war hero General Vo Nguyen Giap has urged the communist government to reconsider plans for a major mining project, warning it would harm the environment and lives of ethnic minorities.

Giap, in an open letter to Prime Minister Nguyen Tan Dung published Wednesday by the online news site VietnamNet, called for a temporary halt to a major bauxite mining project in the Central Highlands region.

"I would like to propose to the prime minister to stop the implementation of bauxite exploitation" until its ecological impact is seriously studied by international experts, wrote the 97-year-old retired general.

Giap still carries much moral authority in Vietnam for leading the defeats of both the French colonial forces and the Americans as the military chief and close confidant of late revolutionary leader Ho Chi Minh.

Dung in a November directive approved the exploitation, processing and use of bauxite ore, from which aluminium is made, state media reported.

The state-run Vietnam National Coal and Mineral Industries Group (Vinacomin) has started building an aluminium factory and is preparing for major mining operations in the Lam Dong and Dak Nong provinces.

Vinacomin is targeting yearly aluminium production of 4.8 to 6.6 million tonnes (tons) by 2015, state media has reported.

The plan has met with protests from scientists and local residents of the mountainous coffee-growing region, who fear the open-cut mining will destroy vast forest and crop areas and create mountains of toxic sludge.

Giap pointed to concerns of scientists and activists about "the serious risk to the natural and social environment posed by bauxite exploitation projects" and added, "However, these projects have still been implemented."

The general wrote that in the early 1980s he had overseen a study on whether to mine for bauxite in the region, and that Soviet experts had advised against the project because of the "risk of serious ecological damage."