Right now, they're buff and bronzed but six surf lifeguards are preparing themselves for a battering when they take on the rough and wild waters of our coastline in a journey around New Zealand.

The men from Muriwai, Papamoa and Devonport clubs plan to circumnavigate the country in an inflatable rescue boat (IRB), the first such trip in such a small craft.

The 40-day trip - inspired by a book and madness, says co-leader Ash Matuschka - is a way of marking 100 years of surf lifesaving clubs in New Zealand.

"We're bloody mad," the 24-year-old admits cheerfully. "It's an incredible thing for a volunteer organisation and we thought, what a great way to capture the spirit of New Zealand and our love of a great adventure."

Matuschka heads the team of experienced lifeguards and support crew who will set off from Auckland's Viaduct on January 5.

He got the idea after reading a book about an American who rowed across the Atlantic.

Matuschka decided to modify the journey as a way of celebrating surf lifesaving clubs, which have boasted 250,000 members over their 100 years.

For six months, the men have been been spending rigorous training sessions at the gym and beach to make sure they are at peak fitness for the trip. "We have to be in the best shape of our lives. There's been a lot of back work because we're going to get shaken up."

And, in what has been a "logistical nightmare" to organise, a support crew will follow the men by road, picking up food along the way.

A second IRB will follow the men on the water, acting as a safety boat.

They will sleep in a motorhome and at surf clubs.

The men will write a regular blog and post photos during their journey on http://www.sixsurflifeguards.org.nz