Fans and former colleagues of Gadsby have been paying tribute to the comedian on social media, pushing his name into the top trends in New Zealand.
Actor and comedian Mark Hadlow said: "With his talent and endless generosity Jon Gadsby helped change Kiwi TV comedy forever. Thank you Jon. Too soon."
NZ On Screen tweeted: "Sad to learn of the death of comedian Jon Gadsby."
It included a link to a "nice interview with him in which he reflects on his career".
Kiwi actor Jed Brophy tweeted: "RIP john Gadsby. Part of making NZ proud to laugh at ourselves."
Comedian and 7 Days host Jeremy Corbett posted: "RIP Jon Gadsby. I grew up on A Week of It and McPhail & Gadsby. V funny man."
Former Prime Minister and administrator of the United Nations Development Programme, Helen Clark, said: "RIP NZ writer & comedian Jon Gadsby: McPhail &Gadsby 1 of best Kiwi TV satirical series ever. Sincere condolences."
Writer Steve Braunias commented: "Jon Gadsby is 'trending' - I think he'd enjoy that. A nice man."
Actor and writer Peter Rowley told Newstalk ZB he would always cherish the last few moments he spent with his close friend.
The pair worked together on shows like McPhail and Gadsby, and Letter to Blanchy.
Rowley saw him just a few days ago, and they watched an episode of Letter to Blanchy together.
Gadsby was very solemn to begin with, he said, but as soon as he heard the theme music his head popped up, there was a smile on his face and a sparkle in his eye. It was the last time Rowley saw Gadsby, and he said it was wonderful.
Matt McPhail, son of Gadsby's former TV partner David McPhail, posted on Facebook: "I'm really really sad to have to say goodbye to the amazing and immensely talented Jon Gadsby QSM tonight. He has been like an uncle to me and he has gone too soon. All my love to his family. Jeez Wayne!"
Peter Rowley, who starred with Gadsby on several popular Kiwi TV productions, including McPhail and Gadsby, posted on Facebook last night: "RIP Jono ... "
Added Dave Ward: "RIP Jon Gadsby. True Kiwi entertainment came from true Kiwis teaching us that it's okay to laugh at ourselves. Thoughts and prayers Peter Rowley, and to his family and friends. Arohanui."
Emily Sorby added: "We lost one of New Zealand's funny guys today ... RIP Jon Gadsby ... Say hello to Billy T for us ... #RIP"
Leading Kiwi comic Jeremy Elwood said he was shocked and saddened at Gadsby's death.
"Came offstage to hear the news about Jon Gadsby. Very sad. We stand on the shoulders of giants," he tweeted.
TV frontman Jason Gunn added: "So sad to hear that Jon Gadsby has died. When I started out, McPhail and Gadsby were in their prime. He was always so generous and genuine. RIP."
United Future leader Peter Dunne also tweeted: "First saw Jon Gadsby as 'Scourer from Mataura' in Otago University revue. Huge talent, will be sorely missed RIP."
Gadsby was born in the UK and completed his school education in Invercargill after his family moved to New Zealand.
His first foray into TV was alongside long-time collaborator David McPhail on A Week of It.
The pair then developed the hit comedy McPhail and Gadsby.
Gadsby was also a noted author, writing and co-writing 45 children's books.
In 1992, he was awarded the Queen's Service Medal for services to broadcasting.
In October his family revealed he was battling cancer. In a statement his family said: "Jon and his family are grateful for the excellent care he is receiving from the medical profession and for the good wishes and prayers from the community.
"His family respectfully request privacy so they can focus on Jon and his treatment -- and supporting him through this."
