"We are concerned about the silence that persists in the world about the struggle for self determination for the people of Western Sahara," Ramaphosa said during a visit to Pretoria by Polisario Front leader Brahim Ghali.
The Algeria-backed Polisario Front movement is campaigning for an independent state in the Western Sahara, a vast stretch of phosphate-rich desert on Africa's northwest coast.
The Polisario proclaimed the SADR in 1976, placing it in conflict with Morocco, which considers the Western Sahara to be part of its own territory.
"It's a just struggle, it's a noble struggle, it's an honorable struggle, a people who want to determine their own destiny though self determination," said Ramaphosa, drawing comparison with South Africa's fight against its White minority apartheid regime.
Rabat controls nearly 80 percent of the territory and is pushing for autonomy under its sovereignty.
But Morocco rejects any vote in which independence is an option, arguing that only granting autonomy is on the table for the sake of regional security.
The SADR is a member of the African Union and says it has been recognized by more than 80 countries.
The dynamics of the long-simmering conflict changed in 2020 when then US president Donald Trump recognized Moroccan sovereignty over Western Sahara in exchange for the kingdom's normalization of relations with Israel.
However, The international community has long backed a referendum to be held to decide the territory's status.