Sir Tim, who served eight terms as Invercargill mayor and two terms as Waitematā mayor making him one of the longest-serving mayors in New Zealand, died last Thursday aged 78.
Pastor Graeme Pope, overseeing the funeral proceedings, described Sir Tim as a "gift".
"I have never met such a sincerely enjoyable person... I could not remember him saying anything unkind."
"The media has focused on his life, which is completely understandable as he did so much.
"But what matters to us, is not so much what he did but who he was.
"He took the time to talk to you, to hear your stories.
Sir Tim's eldest son Robert told the gathering "today we come together to celebrate someone who really, really lived"
Son Ben Shadbolt talked about his father's concrete mixing business, and the pleasure Sir Tim got out of both his business and his activism.
"Not keeping quiet meant he could do so many amazing things,"
"The man, the myth, the legend. My dad Tim Shadbolt."
]Cousin Tui Shadbolt described Sir Tim as "Someone who could roll up his sleeves and make things happen"
"Invercargill become his cause. He had the ability to mobilise people."
Sir Tim, who is being farewelled at Invercargill's Civic Theatre, was made a Knight Companion of New Zealand Order of Merit in the 2019 New Year's Honours List.
A private celebration and interment at Invercargill's Eastern Cemetery would be held after the service.
It will then return down Tweed St on its way to the Eastern Cemetery.
The public is invited to witness the procession and line the streets in "one final tribute to Sir Tim".
Funeral refreshments will be held at Ascot Park Hotel, along with a celebration of Sir Tim's legacy, about 4.30pm.
- Allied Media
