Thousands of fans greeted the 16 competing sides in the American entertainment capital, with a parade journeying down Fremont Street.

Crowds in the region of 50,000 are expected when action begins with pool play at Sam Boyd Stadium.

Olympic champions Fiji will contest Pool A with Kenya, France and Russia, while defending overall Sevens Series champions South Africa, also the winners in Las Vegas last year, have been drawn in Pool D alongside England, Canada and Wales.

Hosts United States will meet Australia, Samoa and Spain in Pool C with Pool D pitting New Zealand, Scotland, Argentina and Uruguay together.

The four legs of the season so far have all produced different winners with South Africa, New Zealand, Australia and Fiji all topping the pile.

It is South Africa who currently lead the way, with 77 points to New Zealand's 69.

Fiji are third on 62.

"This is one of my favourite tournaments, no doubt the crowds really get behind you and it's an awesome venue to play in," said South Africa's Branco Du Preez. 

"I like the fact that the pitch is slightly smaller and play a bit more direct. 

"We have done well in the past and I am determined to contribute to another successful effort and just enjoy the rugby. 

"We are focusing on ourselves and taking it game by game and we really appreciate the support we get here and want to thank the South African fans and everyone in Vegas for making us so welcome."

The top two pool finishers will reach the quarter-finals, with the gold medal game scheduled for Sunday (March 4).