The five firefighters, two of Fire and Rescue NSW and three from the Rural Fire Service, have formed a group to take on the 1504 steps in the city's Centrepoint tower, Sydney's tallest building.

They're joining hundreds of firefighters from across NSW in the 'Firies climb for motor neuron disease', an annual November event.

Retained firefighter Nigel Sharman, who helped organise the team, says the training is going to be pretty tough. They've got just under 150 days to prepare for what will be a very grueling hot climb up the skyscraper on November 9. The tower is 309 metres high, 98 storeys, and he's planning to do the climb in 20kgs of firefighting kit.

He said he was motivated by the challenge.

"It's the challenge of climbing a tower, climbing Centrepoint, it's the challenge of wearing firefighting gear; all of that put together is going to be a challenge in itself.

"Just the fitness, nearing the fitness to get to that stage (will be a challenge).

"Also the challenge is raising money that goes towards motor neurone disease.

"I'm not personally affected by motor neurone disease but I guarantee there are people in town who are. So I'll be happy to think we'll be doing for a good cause towards raising money to help maybe one day find a cure for them or future people."

The event has raised over $2 million since 2015 and a ticker on the climb website said at time of printing they had already raised $57,589.87 this year.

Nigel said their team formed early because there is a limited number of spaces that fill up quickly. Application opened in May and is very nearly full just over a month later.

He said he needs to improve his fitness "a lot" to tackle the challenge. Nigel King at King's gym is getting on board to help them plan PT sessions.

They're hoping to raise $2000 between the six of them. They're planning meat raffles and other events to raise the cash.

"If everyone just put $10 in that's a big difference, it all goes towards (it)," he said.

This is the first time Glen Innes has entered a team.

Motor neuron disease, also known as Lou Gehrigs Disease, is the name for a group of horrendous muscle degenerative disorders that gradual destroys your ability to control your own voluntary muscles, eventually causing death. It has no cure. Some are born with the disease as children, but it can also affect adults.

Scientist Stephen Hawking lived with the disease for 45 years.

Centrepoint tower, on Sydney's Market Street, is also known as Sydney Tower.