The delegation includes Prime Minister Stephen Harper, as well as three of his predecessors — Brian Mulroney, Jean Chretien and Kim Campbell — and other Canadian premiers.
McNeil will attend memorial events for Mandela while in South Africa, including his lying in state in Pretoria on Wednesday.
"The world has lost one of the greatest leaders and humanitarians it has ever known," said McNeil in a statement on Sunday.
"His life and teachings will continue to have a positive impact on people around the globe, and I am honoured to accept the prime minister's invitation to pay respects on behalf of the people of Nova Scotia."
Mandela died on Thursday at the age of 95.
His body will lie in state from Wednesday through Friday.
A state funeral for the former South African president is planned for next Sunday.