SAO PAULO (Reuters) - South Africa has advanced in talks for a potential purchase of Embraer's C-390 Millennium, the Brazilian planemaker said on Wednesday, after showcasing the military cargo aircraft in the African nation for the second time.

The company voiced optimism about clinching a sale as South African authorities said they were advancing in the "necessary steps for the selection of the much needed" aircraft for its National Defense Force, according to a statement.

Embraer did not detail how many planes could be sold or at which stage the process was.

A potential deal would represent the first C-390 sale to an African country. The plane has so far been tapped by developer Brazil as well as Portugal, Hungary, the Czech Republic, Austria, the Netherlands and South Korea.

The multi-mission aircraft, which competes with Lockheed Martin's C-130, "is perfectly suited to replace the legacy aircraft currently in service with South Africa," Embraer said.

The Brazilian company presented the C-390 to President Cyril Ramaphosa and Defense Minister Angie Motshekga at the Africa Aerospace and Defence exhibition held earlier this month at the Waterkloof Air Force Base, it said.

Brazil and South Africa are both members of the BRICS group of major emerging economies.