Former SDLP South Antrim Assembly member Donovan McClelland has died aged 69.
Party leader Colum Eastwood said he had a sharp mind and warm heart and served the party with distinction as a councillor, Assembly member and deputy speaker at Stormont.
He died on Friday morning.
Mr Eastwood said: "His contribution to peace on this island as an SDLP delegate to the Brooke/Mayhew talks and later in the negotiations that led to the Good Friday Agreement have left an indelible mark on our political dispensation.
"His was a life with a lasting legacy and one filled with love for his family."
He extended his sympathies to Mr McClelland's wife Noreen.
SDLP deputy leader Nichola Mallon MLA said he made an impact on the lives of everyone who knew him and would be sadly missed by many.
"The contribution that he and his wife Noreen have made to peace and politics here cannot be overstated.
"They have given up so much to help people and communities most in need."