Former Deputy Prime Minister Jim Anderton was farewelled at a ceremony at Sacred Heart Catholic Church in Addington, Christchurch, on Thursday afternoon.
His son, Chris Anderton, performed Tom Petty's 'I Won't Back Down', a song he said is his father's "personal anthem".
He said his father once commented that he loved the song, which was chosen to accompany a news story about him in the 1980s.
"Being children of a public figure can be a heavy load. But if I was ever going to choose a father to be a public figure, it would be you Dad. Your empathy for those less fortunate than yourself, your honesty, trustworthiness and sense of fellowship toward all people are qualities that not only your children admire and respect, but a grieving public."
Among those at the funeral were Prime Minister Jacinda Ardern, Christchurch Mayor Lianne Dalziel, New Zealand Council of Trade Unions secretary Sam Huggard, Labour Party general secretary Andrew Kirton, National MP Gerry Brownlee and former Prime Minister Jim Bolger.
Mr Anderton died in Christchurch's Cashmere View Hospital on Saturday, aged 79.