President Michael D Higgins has told world leaders the best way to honour Nelson Mandela is to use his values to deal with modern day challenges.
Heads of state from around the world attended the event in the South African capital Pretoria as thousands of people filed past the freedom fighter's remains in the city's Union Buildings.
The coffin holding Mr Mandela will be on display in South Africa's main seat of power for the next three days with queues to pay respects at some stages as long as 3km.
Mr Higgins said that he was honoured to speak to the leaders.
"Nelson Mandela's legacy will last not only for Africa but for the world," he said.
He said Mr Mandela's speeches in European capitals following his release in 1990 breathed great courage into movements including the ending of apartheid.
"He had a great combination of head and heart, intellectual strength and emotional power. The best way to honour his values is to bring them to the centre of challenges facing our times," the President said.
"We should follow Mandela's example in bringing creativity and flexibility to challenges of global poverty, inequality and to have the courage to bring new forms of solidarity into existence in international economics, trade, politics and diplomacy."
Mr Higgins said that to have met Mr Mandela was "to be in the presence of the great grace of the human spirit".
"He would want us to continue his efforts to put the stamp of humanity on our times for the sake of future generations," he said.
A spokesman for the President said he had been asked to address the lunch by South African president Jacob Zuma on behalf of the heads of state of the European Union.
Mr Higgins paid his own respects to Mr Mandela before he spoke.
Mr Mandela will be moved to his final resting place on Sunday, when he will be buried at his childhood village of Qunu in Eastern Cape Province.