The park in the north of the largely desert nation is home to 114 species of mammals, notably the critically endangered black rhinoceros, and is a major tourist attraction.

The fire started on September 22 and spread rapidly because of strong winds and dry vegetation, causing extensive ecological damage, the environment ministry and presidency said.

The tourism ministry announced it had closed certain tourist routes and warned visitors to be cautious as the wind direction could change unpredictably.

After an emergency cabinet meeting Saturday, the government deployed 500 troops and two helicopters to the area on Sunday to help fire-fighting efforts, the presidency said in a statement.

The reinforcements joined 40 soldiers who arrived on Saturday to assist police, locals and people from nearby farms and private enterprises who had already been fighting the flames, it said.

The extra troops "are deployed from various regions and will be deployed to all affected areas," Defence Minister Frans Kapofi told AFP.

"An unknown number of wildlife had been killed, whilst, thankfully, no human casualties have been reported," the presidency said, adding that the blaze had spread into some communal areas.

"The fire poses a significant threat to the biodiversity, wildlife and livelihood of the communities in the affected areas.

Approximately 30 percent of the grazing in the park has been destroyed by the fire," it said, adding it was still trying to establish what ignited the blaze.

The environment ministry said Saturday at least nine antelopes had been killed in the blaze, which was believed to have started from charcoal production activities on commercial farms bordering Etosha National Park (ENP).

"The ecological damage inside ENP is extensive, with an estimated 775,163 hectares (1.9 million acres), approximately 34 percent of the park, burned," it said.

The presidency said information provided by teams on the ground indicated that the fire was under control Sunday in some regions but mainly continuing in the Omusati region near the border with Angola.

The park stretches across 22,270 square kilometres (8,600 square miles) and its main feature is the ancient Etosha salt pan, which is around 130 kilometres long and 50 kilometres wide and draws huge flocks of migratory flamingoes during the rainy season.