South Korea's opposition-controlled National Assembly voted to impeach acting President Han Duck-soo despite vehement protests by governing party lawmakers, further deepening the country's political crisis.

Finance Minister Choi Sang-mok became on Friday South Korea's second acting president in two weeks, as lawmakers voted to impeach the current acting leader, Prime Minister Han Duck-soo, fuelling political uncertainty in Asia's fourth-largest economy.

Han has been the caretaker leader after President Yoon Suk Yeol was impeached by the assembly over his short-lived imposition of martial law earlier this month.