The party made the request in a letter sent last week to US Secretary of State Antony Blinken and some European foreign affairs ministers.

“The DA’s letter to the United States government is quite disingenuous and it is almost trying to sell our country to other powers in the world," President Ramaphosa was quoted as saying by state broadcaster SABC.

"And we have regional organisations in the world like Sadc, AU and have the UN as well. They always come to monitor our elections and now for a non-state entity to sell our democracy.”

The ruling African National Congress (ANC) party also slammed DA for the letter on Saturday, accusing the opposition party of offering "South Africa's sovereignty on a silver platter".

South Africa's elections are planned for 29 May.

Polls by research firms suggest that ANC's share of the vote could fall below 50% for the first time since it came to power in 1994, fuelled by widespread dissatisfaction with the state of the economy, public services and corruption.