Organisers deemed that moving the event to November 5 to 7, as opposed to its usual April window, would give the HKRU the best chance of staging the event.

It was set to take place from April 2 to 4 before the move, while the 2020 edition was cancelled due to the initial COVID-19 outbreak.

"Given increasing infection rates both at home and abroad, an ongoing travel restrictions and quarantines, it was felt that the environment remains too uncertain to support hosting the event next April," read a statement.

World Rugby has also confirmed that the Hong Kong Sevens tournament in November will be the final round of the 2020-2021 World Rugby Sevens Series.

It is expected that the 2022 edition of the tournament - one of seven-a-side rugby's flagship events - will return to its usual place on the calendar, in April.

"We are disappointed at not being able to proceed with our detailed operational planning for April, but will press ahead with planning for November, when we hope that global vaccination efforts may support the easing of travel quarantines and local gathering restrictions and enable us to host the type of Sevens to which fans the world over are accustomed," HKRU chief executive Robbie McRobbie said.

"Absence, we hope, makes the heart grow fonder, so we are confident that a November Sevens will ensure a very unique, if long delayed, celebration of the 45th Cathay Pacific/HSBC Hong Kong Sevens."

It means the tournament is set to be hosted outside of its traditional spring window for the first time in its 45-year history.

The final four rounds of last season's Sevens Series were eventually cancelled due to the global health crisis, resulting in New Zealand being crowned men's champions after just six rounds.

New Zealand also won the women's title.

Speaking to the South China Morning Post, McRobbie added that the tournament would only go ahead if at least 50 per cent of the stadium could be filled with spectators.

"We've always said that an event with no crowd makes no sense for us," McRobbie said.

"That's the nature of our commercial model.

"We don't make any money from broadcast - that goes into the central pool with World Rugby - so we are very reliant on bums on seats and sponsors, patrons and corporates in the stadiums.

"We have done the figures and know what number crowd we need to get to the stadium.

"As long as we've got 50 per cent or more, the event makes commercial sense for us.

"That's what we'll be working towards, the benchmark of 50 per cent, below it and we would need to reconsider."