A district court judge is swapping his robes for exercise gear to help mentor a group of Porirua students heading to the Coast to Coast.

Judge Arthur Tompkins, normally found in the Hutt Valley District Court, is pulling strings to help four teenagers from Aotea College make it to the iconic multisport event in the South Island next year.

The students — Tom Gibbs, 16; Axel af Klercker, 17; Toby Devine, 16; and Ryan Tait, 17 — even have the backing of Prime Minister Jacinda Ardern, who sent a video message encouraging them.

Ryan remembers when the idea of participating in the 243km race from the west to the east of the South Island was first raised in a school assembly, and a friend turned to him and suggested they put their names forward.

Judge Arthur Tompkins with the Aotea College Kathmandu Coast to Coast Academy team, from left, Axel af Klercker (kayak), Toby Devine, Tom Gibbs, and Ryan Tait. Photo / Mark Mitchell
Judge Arthur Tompkins with the Aotea College Kathmandu Coast to Coast Academy team, from left, Axel af Klercker (kayak), Toby Devine, Tom Gibbs, and Ryan Tait. Photo / Mark Mitchell

"[I said] 'Jake, it's the Coast to Coast, we're not doing that.'"

But come February next year Ryan will be strapping on a helmet to do his part in the gruelling event, which involves sections of cycling, mountain running and kayaking.

The race begins at Kumara Beach and ends at Brighton Beach. The team will take two days to complete it.

"It will be quite cool doing such a hard event in one of the most beautiful places in the country," Ryan said.

Axel, who is in New Zealand as a Swedish exchange student and will be doing the kayaking, said he was most looking forward to the scenery.

He has been out kayaking six times a week to train for the race.

Tompkins warned him it would be like spending "five hours on a freshwater rollercoaster".

Tompkins, who has done the Coast to Coast for the past six years, said kayaking in the Waimakariri Gorge, which is part of the route, was "just spectacular".

"It's the closest thing we've got to the Grand Canyon. It's unbelievably wonderful."

"As I did when I first started out doing Coast, it may well be the totally unexpected that provides them with moments of joy along the way — the sudden glimpse of a towering waterfall, the sweeping vista of the mountains, the ice-blue colour of the Waimakariri River in the early morning sun ... and the incredible buzz of running down the finish chute on New Brighton beach cannot be overestimated.

He had the idea to get in touch with Aotea College principal Kate Gainsford, who he went to university with about 35 years ago, and offer his mentorship.

He said it meant a lot to be able to help.

"It means giving back to the community, and it means demystifying the sometimes unrealistic and distant [or] isolated perceived role of 'the judge' in our community."

Gainsford said to the best of her knowledge it was the first time any of their current students had gone to the Coast to Coast.

"It's been an extraordinary team effort and that's just to get us to this point. What's going to happen now is going to be even more extraordinary," she said.

Tom, who is running about 50km each week in preparation for the event, will be doing the mountain run. He was not looking forward to how his legs would feel the day after the race.

The boys will have one day of rest before going back to school the following Monday.

"I better see you all here Monday, boys," Toby said.

Toby is joining the staff team instead, and will be kayaking as well.

He was excited about doing something new and having fun at the same time. He said it was an achievement to be able to go at all.

The boys have beaten three others schools in winning a support package from Kathmandu, the event's main sponsor.

The Kathmandu Coast to Coast Academy will support them by providing some specialist equipment, including a bicycle and a kayak to train and compete with, mentoring and coaching from nine-time race winner Steve Gurney, free camping at the site, and help to put Axel through a grade-two kayaking course.