They say only fools and horses work, but it would surely take a particular kind of fool to take on a horse over a 40km race?

If it sounds like an idea tossed around after a few too many beers at the pub you'd be right, that is exactly where the idea for 'The Only Fools and Horses Race' came to life.

Runners and horses will go head-to-head in a race through rugged terrain of Maniototo in central Otago.

While horses can average speeds of up to 40kmh, humans typically run at around 10kmh, but who will have the endurance to go all the way?

The idea came about at the Wedderburn Pub on the Central Otago Rail Trail, Only Fools and Horses Race coordinator Steve Tripp told RNZ's Afternoons.

"We've got a 40km route in Wedderburn, it's entirely on private land, and the local landowners have been awesome and letting us access their properties.

"It's quite beautiful, it starts and finishes at Wedderburn cottages across the road from the pub, and this is in the Maniototo, so you've got wide open plains, you've got tussock land goes up into the surrounding hills. So, it's some beautiful scenery."

The race will comprise 60 horses and a maximum of 200 two-footed contestants, he said.

"Most of it's fairly runnable. There is a bit of a steep uphill, which possibly some of the horses will do quicker. And there's a steepish downhill, which possibly runners will do quicker.

"Any single section, I think you'd say the horses would do better, but over 40kms, who knows, it's going to be close."

A famous human vs horse race takes place in Wales every year - and the horses have so far had the edge, he said.

"It's been going about 40 years, and I think humans have won it four times.

That 40km distance is the key, he said.

"If you look at the endurance of humans against horses, horses obviously are a lot faster, but as they go for longer, they can't go so fast, because they don't sweat as much, and they've got too much fur and they overheat and stuff like that.

"So, they reckon that 40kms, around that time, is kind of the sweet spot where humans start to have an advantage after that distance."

There will be vet checks at the race to make sure the horses are well and happy, he said.

It will also be a staggered start, he said, avoiding a starting line crush.

"The humans start 15 minutes before the horses. We will take 15 minutes off their time, so it still counts the same.

"Then the horses get to catch up. And so by then, the humans are all spread out and the horses will all be spread out."

It could be a classic photo finish, he said.

"The horse will probably win, but, you know, it can get hot in the Maniototo."