No country has the right to intimidate another, South African President Cyril Ramaphosa said on Thursday, in an allusion to the United States boycotting the G20 summit hosted this weekend by South Africa.

Washington, in a diplomatic note dated November 15, cited its absence from the summit to deny Pretoria the possibility of issuing a joint statement at the end of the meeting, which brings together the world's major economies.

"It is not possible for a country, based on its geographical location, its income or its army, to determine who can speak and who does not have a say," said the South African president at an event bringing together civil society organizations ahead of the summit scheduled for Saturday and Sunday.

"This simply means that one nation should not bully another," he added.

Since returning to the White House in January, US President Donald Trump has launched numerous virulent attacks against the Pretoria government, citing alleged persecution of a white minority and imposing the highest tariffs for a sub-Saharan African country (30%).

In its note to South African diplomacy, the US embassy confirms the absence of any American representation at the summit.

"South Africa's priorities for the G20 run counter to the political views of the United States and we cannot support a consensus on the documents negotiated under your presidency," the note, seen by AFP, stated.

"If a result is published during your presidency, it will be presented solely as a statement from the (South African) president in order to accurately reflect the lack of consensus," the embassy said.

South African Foreign Minister Ronald Lamola indicated that Pretoria would continue its efforts to obtain a joint statement from the leaders present.

"We will not let any party absent (from the summit) tell us that we cannot adopt a declaration or make decisions at the summit," he said on Thursday, after President Ramaphosa's speech.

The theme of the South African presidency, "Solidarity, Equality, Sustainability," focuses primarily on debt relief for developing countries, financing adaptation to climate change, and combating economic inequality. US Secretary of State Marco Rubio had deemed it "un-American" in February.

South Africa is the first African country to host a G20 summit, whose members - 19 countries plus the European Union and the African Union - represent 85% of the world's GDP and about two-thirds of its population.