A team of Australian gardeners have created history by claiming best in show honours at the prestigious Chelsea Flower Show in London.

The Trailfinders Australian Garden exhibit, which took a team of 18 volunteers 17 days to build, features a stone gorge, running waterfalls and a billabong.

The $2 million display was designed by Melbourne's Phillip Johnson and is the first Australian display to win best in show.

It was also awarded a gold medal at the Royal Horticultural Society event.

Mr Johnson says his win is a mind-blowing achievement.

"I've just had people from Australia grab me and say 'you've done Australia proud'," he said.

"And that's what we've all gone out to do, to try to do the best possible job.

"We've nailed it. This is an amazing feeling, I'll tell you that."

The Trailfinders Australian Garden exhibit took a team of 18 volunteers 17 days to build ( AAP: Chelsea Flower Show/Tim Whitby )

Mr Johnson says he was inspired by family holidays in the Grampians in western Victoria.

"It's just the beauty of the Australian outback," he said.

His team-mate Wes Fleming, who has entered the competition a total of nine times, also hailed the win.

"You can't imagine it," Mr Fleming told AAP.

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"I never thought it would happen but as I've told the crew about 20 times this morning, we can go home knowing that we're the best in the world at what we do.

"We've had 18 volunteers taking six weeks out of their lives, they're the best in the world and I couldn't be more proud to be Australian."

The Chelsea Flower Show is open to the public from May 21 to 25 in the grounds of the Chelsea Hospital in London.

Philip Johnson (centre) and the Fleming's nursery gardening team celebrate their win ( Supplied )

ABC/AAP