Sir Bill, a former England international, is aiming to retain his post as current chairman of the sport's governing body, but is being challenged by Agustin Pichot, a former Argentina international and current vice-chairman, for the role.

Ahead of voting closing tomorrow, the WRU Board has become the latest union to publicly declare its stance.

WRU chair Gareth Davies explained as well as a meeting of the WRU Board, the organisation also consulted the Professional Rugby Board (PRB) and its own Executive Board before backing Beaumont.

"We have spoken to both candidates and assessed their manifesto commitments in turn," said Davies.

"We have digested the dynamic drive for change presented by Agustin and understood the commitment to progress but also stability and the steady hand provided by Bill.

"Some members of our Board expressed direct support for Bill and others acceded to take their steer from those of us who are closest to the issues at play. 

"There were members of both our Executive Board and the PRB who expressed a preference for Agustin, and this was by no means a ‘one horse race’ in the Board’s eyes, but our final collective decision was reached based on evidence provided, due diligence and research of each candidate.

"We are strongly of the belief that this was the proper way to conduct ourselves, just as when we were deciding on how to vote for the 2023 Rugby World Cup host candidates – where we followed the recommendations of the technical evaluation conducted by World Rugby.

"We have followed the evidence before us and, we are sure, backed the best candidate for the job."

The WRU's backing for Sir Bill comes a day after Rugby Europe after also threw their support behind the 68-year-old, saying his manifesto "corresponded to the priority actions necessary for the development of rugby in Europe."

Meanwhile, Asia Rugby overwhelmingly backed Pichot for the position, with their President Qais Abdulla Al Dhalai saying he believed the Argentinian's vision would "enable greater playing performance for Asia and all regions including emerging unions."

Under the current voting system, 30 of the 51 votes are allocated to the 10 Tier one unions within the Six Nations and Rugby Championship tournaments.

Two votes go to each to the six regional associations, plus Japan gets two votes and there is one vote for each for the seven unions from Canada, the United States, Uruguay, Georgia, Romania, Samoa and Fiji.

Although voting closes tomorrow, the result will not be announced until May 12, along with the result of the votes for vice-chairman and the Executive Committee.