Bryan Wyness travelled hundreds of thousands of kilometres across some of the most wild and remote terrain on earth.

But it was a stretch of State Highway 1 at Rangiriri only a short ride from his Pukekohe home that took the life of the prominent businessman and motorcyclist.

Mr Wyness, 71, died yesterday after losing control of his motorcycle and hitting a median barrier. He was one of six "Silk Riders" - a group which included high-profile economist Gareth Morgan - to conquer the three-month near 20,000km Silk Road trip from Venice to Beijing, in the footsteps of Marco Polo in 2005.

The tour received widespread publicity with Mr Morgan and his wife Jo writing a book - Silk Riders - about their travels.

Mr Wyness was riding the same BMW F 650GS touring bike that carried him across the mountainous passes and burning plains of central Asia when he died yesterday but police are baffled over what caused the smash.

Waikato road policing manager Inspector Leo Tooman said it appeared Mr Wyness was travelling in the left, southbound lane of the expressway when he lost control, about 600m south of the Rangiriri tavern and veered into the right hand lane and crashed. There was only minor contact with the wire barrier.

Mr Tooman said he believed Mr Wyness was travelling very slowly when he crashed, leaving investigators puzzled as to the cause until an autopsy can be held.

No other vehicles were thought to be involved and police appealed for witnesses to come forward.

Fellow Silk Route rider and Fisher and Paykel director Phil Lough was shocked to hear of Mr Wyness' death, especially with his extensive background in safety. He was the owner and co-director of New Zealand Safety Management Systems and Fatigue Risk Management Systems.

Mr Wyness's friend of 20 years, Mike "MOD" O'Donnell, said the country had lost a man with a "gregariousness that was extraordinary".

"Brian has negotiated some of the toughest roads in the world, through Central Asia through all sorts of four-wheel-drive and off road tracks in New Zealand, through 20 brass monkeys in snow and ice and to die on a normal stretch of road on hard pack is a little ironic," Mr O'Donnell said.

Mr O'Donnell, head of Trade Me operations, last saw his friend - known as "The Captain" to his mates - about five weeks ago on this year's Brass Monkey motorcycle tour which travels through Central Otago.

"When I met Bryan in 1994 he was the global head of the international airline for Air New Zealand, chief pilot of international pilot operations. He's also a former director of Air NZ.

"He basically commanded all of the international flight operations for Air NZ for a long time and prior to that was a 747 pilot himself."

In 2004 Mr Wyness was appointed to the Transport Accident and Investigation Commission, and was chair of the New Zealand Royal Opera School Board in Wanganui.

Mr Wyness had a huge passion for motorsport - owning three motorbikes, including a Harley Davidson, and four Jaguars.

"He was one of the country's top Mini racers and had one of the fastest Mini Cooper S's in New Zealand," Mr O'Donnell said. Together the pair did 18 Brass Monkey tours and it was during those meets the Silk Rd tour group was formed.

Despite his feats in the business and sporting world - overcoming cancer was one of his biggest achievements.

Mr Wyness was incredibly fit and discovered a love of marathons late in life, clocking approximately 40.

"He had such huge character, celebrated life, celebrated people and really understood mateship," Mr O'Donnell said.

"But I guess most of all I would describe him as a true renaissance man. He was as comfortable in a set of tails with (his wife) Marion at the opening of an opera season as he was on the side of a road with a motorcycle jacked up on the back of a beer crate trying to do an impromptu fix in the middle of nowhere."

- © Fairfax NZ News