World tennis chiefs on Thursday approved a radical Davis Cup revamp that will overhaul the 118-year-old competition, condensing the annual worldwide showpiece into an 18-team, week-long event.

The shake-up for the men's team tournament received 71.43 per cent support from about 120 delegates at the International Tennis Federation annual meeting in Orlando, well ahead of the two-thirds majority needed for approval.

ITF president David Haggerty supported the revamp proposed by Kosmos, a group led by Barcelona football star Gerard Pique – who flew in from Spain for the vote – and backed by Japanese billionaire Hiroshi Mikitani, that has vowed $3 billion over 25 years to support the new event.

Haggerty called the reform plan “key to ensuring that the ITF and its member nations will guarantee a bright future for the sport.”

Also backing the reconstituted event is US billionaire Larry Ellison, who hopes his Indian Wells tennis facility would host the 2021 edition of the finals after the first two were played in Europe.

The current Davis Cup format is a knockout event played February, July, September and November at home and away venues around the globe, best-of-five match ties following Grand Slam events until the final round.

Many top players have skipped it in recent years to ease their schedule load.

The reform plan will create a November finals with 18 teams: 12 winners from 24-team home and away qualifying in February, the prior year's four semifinalists and two wild-card nations.

Round-robin groups of three would send six group winners and two runners-up into knockout round playoffs.

The finals would feature two singles matches and one doubles match each day, all cut to best-of-three sets.

Haggerty said the arrangement would provide about $25 million annually for national tennis associations to invest in grassroots level support, with the United States, France and Spain among those thought to support the move.

Opponents of the plan include Tennis Australia and Britain's Lawn Tennis Association (LTA), with Aussie Davis Cup captain Lleyton Hewitt calling it a “money grab” and too great a departure from the current format.

“Unfortunately their plan is a recipe for the death of the Davis Cup as we know it,” Aussie legend John Newcombe said.

The LTA cited concern over holding the event in November, stretching the schedule after the ATP season finale into an already-thin off-season, risking top player attendance, fan support and telecaster interest. The LTA also wanted more clarity on financial issues and a plan with greater unity among membership.

Complicating the landscape is the revived ATP World Team Cup set for January 2020 with 24 teams, prize money and rankings points to be played in Australia ahead of the Australian Open.

It would be staged just six weeks after the Davis Cup event, scheduling that ATP executive chairman Chris Kermode described as “insane.”