The former Port Stephens councillor who died on New Year's Eve remained an activist to the end, and beyond, by apologising to future generations in a letter written shortly before his death, and assuring them not to be afraid to fight for the planet.

"My one regret is that my generation has not been kind to the planet and has left a terrible legacy for my grandchildren to try and clean up, and for that I apologise to them," Mr Dingle wrote.

"For every tree and shrub Libby and I planted, others were destroying thousands. I have great faith in the next generation to get it right. My final words to them and those present - if you want to make a difference, get engaged. Whingers deliver negative vibes and never make a difference so ignore them, and don't be afraid to tell them to shut it, unless they have something to contribute."

Mr Dingle started work at BHP in 1969 as a structural engineer, married wife Libby in 1978 and moved to Medowie the following year. Although they travelled Australia and the world and considered moving elsewhere after Mr Dingle retired, they could never leave, Mrs Libby told the standing room-only crowd at Medowie's Pacific Palms in a moving tribute to her husband.

Port Stephens MP Kate Washington wept for the friend she admired, who "knew right from wrong" and "had an astute radar for bull....".

"He could smell a rat and goodness knows there were just a few smell. He relied on a strategy which was pretty simple. It's called telling the truth. There were a few people who didn't particularly like him for doing that, as we know. And because Geoff was sometimes the only opposing voice, he was targeted, sometimes in ways that were not only unfair, but they were grubby and offensive," Ms Washington said.

"It played out publicly and it was designed to hurt him at a very personal level. And despite those efforts, and despite those people who were around him he continued to work for his community, shining a light on matters that were not in the community's interest."

Ms Washington praised Mr Dingle for his ethics, but also his practical contribution to Port Stephens as a councillor for 14 years, and particularly the Medowie area.

"There is hardly anything in Medowie that Geoff hasn't had a hand in. Either establishing it, running it, improving it, or making it work better," she said.

Ms Washington was in tears as she spoke about Mr Dingle's death from pancreatic cancer, aged 69.

"This wasn't fair. If anyone deserved a long and peaceful retirement, it was Geoff," she said.

A number of speakers acknowledged Mr Dingle's ability to "call a spade a bloody shovel".

Tomaree Ratepayers and Residents Association leader Dick Appleby acknowledged Mr Dingle was "a major handful for any chairman" but he was also "a very public whistleblower" of Port Stephens Council's "waste of public money" on issues including the long-running Lagoons case.

The crowd applauded when Mr Appleby spoke of Mr Dingle receiving his Freeman of the City of Port Stephens award last year by post, which he handed back to the council "so that it could be signed and presented properly".

"He told me he parked in a freeman's parking spot at the council to make a point," Mr Appleby said.

He slammed the council for its failure to apologise to Mr Dingle after leaking a discredited code of conduct report that was "an outrageous slur".

Pauline Avery, who was on a number of community committees with Mr Dingle, said he was an advocate for many but was also a hands-on community leader.

"He was always at the end of a shovel. We were always digging something somewhere," Mrs Avery said.

"The parks in this area are a real tribute to him. I just miss him," she said.

In his final letter Mr Dingle reminded people to "stop and smell the roses while you can because the basic pleasures in life are the best and often cost nothing".

"The most pleasurable things in life are simplest. Just sitting on the patio, drink in hand, and watching a family of fairy wrens making a home in our backyard."

He had a final message for young and old.

"The blue planet is under so much pressure to support the human population, and humans have devastated the environment in so many ways," he wrote.

"It's over to my children and grandchildren to take up the challenge. I'd love to have been around when electric cars are the norm and petrol-guzzling polluters are frowned upon; when planting trees is the norm rather than knocking them down, and digging stuff up is frowned upon.

"It's all going to happen because there are no other options. I hope my generation gets out of the way for future generations."