The hill climb category of the Feb 7-11 event is taking place today.
The changes were made after two accidents at the 2023 event.
The two separate accidents left one person critically injured, three seriously injured and a fifth was taken to hospital in a moderate condition while several others were also treated at the scene.
Racing had continued after the first accident in the morning, but spectators were removed following the second crash in the afternoon.
Barriers and crowd marshalls had been in place on the hill, but one rider came off his bike and slid into the crowd. He was uninjured.
Mr Underhay said an intensive 10-month review was undertaken as a result of the accidents.
"Last year’s event was very unfortunate and brought to the forefront motorcycling is a dangerous sport.
"Within a week of that event taking place, there was a total debrief within ourselves ... including our governing body.
"This year’s there's been an awful lot of changes and we're hoping it will benefit everybody and we're very confident that it's going to be better."
The public would now have restricted access.
"We have added, in some areas, three layers of protection for both marshalls and public, but the main one was the public would now be contained in four areas so they can’t walk freely any more like they used to.
"We used to rely on the public having a modicum of common sense. We’ve had to take the common sense out of it and restrict them where they can and cannot go to make it safer", he said.
He hoped the changes would enhance safety as well as give people better viewing areas.
The club had also been investing in infrastructure items such as fencing, barriers and effective communications equipment.
The Burt Munro Challenge has been an annual event started by the Southland Motorcycle Club and hosted in Invercargill since 2006.
The club created the event to honour former Invercargill motorcycle enthusiast the late Burt Munro, who holds the under-1000cc class world land speed record of 295.453kmh set in 1967 on his 1920 Indian Scout on the Bonneville Salt Flats in Utah.
His achievements inspired the 2005 movie "The World’s Fastest Indian".
Since the movie’s release, the annual rally has gone on to become one of the largest motorcycle rallies in the southern hemisphere.
— Toni McDonald
