Two men, a kayak, and a 400 kilometre paddle for the climate crisis

And his retirement is long shot from the quintessential trope of a quiet life with the grandchildren. Armed with a kayak, he's on a 400-kilometre mission to fight climate change.

The 70-year-old began paddling on November 5 from Lake Illawarra to Newcastle for The People's Blockade of Newcastle coal port.

"It was sort of a personal challenge," Mr Hunt said of a trip which at times made him seasick and hypothermic.

A former BHP systems engineer, Mr Hunt said he first became concerned about climate change when he considered how his home and hundreds of others on the Lake Illawarra waterfront would be "wiped out" if sea levels rose.

From there, he said he learnt that a rise in sea levels and excess carbon into the atmosphere would devastate the next generation. And he quickly became an activist.

"I brought this same kayak with me [to Newcastle] in 2016 and sailed with the same sign: 'no more fossil fuels'.

"When I heard about this [2023] blockade being planned, I'd been looking for a challenge in kayaking," he said. "I started kayaking on Lake Burley Griffin with a different sign [before] starting this journey."

Mr Hunt said he and his university classmates knew about the potential impacts of climate change in the 1970s, but only recognised the severity of their actions in hindsight.

"Like everybody else, I just ignored that and continued on in my ways," he said. "I'm as much to blame as anybody in my generation."

Rising Tide member Naomi Hodgson, who is helping organise the blockade, said retirees would have a "disproportionate" representation on the weekend.

"They have time," she said. "And they care about [the future] for their grandchildren."

Mr Hunt will be adding to those numbers with his mate, retired medical doctor Simon Leslie. The men run in similar circles for climate action, but hadn't seen each other for several years when they decided to do the Wollongong to Newcastle paddle as a duo.

"It was Tom's idea," Mr Leslie said. "He told me he couldn't find anyone to go along with him. I always like a little bit of adventure so I said: 'Yea, I'll do that!' I've always been very concerned about this climate crisis.

"It's wonderful being out on the ocean. In [the kayak] you are so close to nature. You're sitting on the water and the wind is brushing past. The birds, the sea life. It's good," he said.

Mr Leslie said he had found the public attention "very difficult". The pair, who have coined the name 'Sail 4 Sanity', have been welcomed by large crowds in most places they have stopped, including Port Kembla, Botany Bay, Terrigal and Norah Head.

"I don't like being in the spotlight," Mr Leslie said. "But that is part of what we are doing. It's [important]."

They will formally arrive in Newcastle at 10am on Friday.