While Sinn Fein mayors in Belfast have laid a laurel wreath in previous years, this will be the first time the party leadership will take part.
While Sinn Fein Lord Mayors in the capital have laid a laurel wreath on the anniversary of the First World War battle in previous years, this is the first time a member of the party’s leadership will take part.
Ms O’Neill will join the current Belfast Lord Mayor Tina Black to lay wreaths in a low-key ceremony on Friday morning, ahead of the official commemorative event marking the first day of the battle.
The Sinn Fein Stormont leader, who will be entitled to be nominated as First Minister when the Assembly is revived as leader of the largest party in the Assembly, said she is demonstrating her commitment to work for everyone.
Last July, the then deputy First Minister joined then first minister Paul Givan of the DUP at the Irish National War Memorial at Islandbridge in Dublin to remember those who fell at the Somme.
That was then the first time the Sinn Fein politician had attended a Royal British Legion wreath-laying ceremony.
She told the PA news agency: “Tomorrow 1 July, I will join Mayor of Belfast Tina Black to pay respects to all those, Irish and British, from our island who were killed at the Battle of the Somme 106 years ago.
“I believe it’s important that as first minister designate, that I demonstrate my commitment to work for everyone and work to strengthen cooperation and friendship between those of us in political and public life and the people we represent, from all traditions.
“If we are to heal all the wounds of the past and build a better future, we must acknowledge the loss of those killed in war and conflict as experienced, honoured and commemorated by those they left behind.”
Ms O’Neill added: “We must also seek to identify with the grief, the hurt and the suffering as something we all share; an approach based on common humanity.
“This is part of our shared history.
“I believe however that all political leaders must stretch themselves to seek common ground and that’s what I am committed to doing every single day.”
The Battle of the Somme was one of the largest and bloodiest battles of the First World War.
It saw the 36th Ulster Division and the 16th Irish Division, representing the two main traditions from Northern Ireland, distinguish themselves, but at a great cost.