A unique 2030 World Cup is set to be played in Europe and Africa, with the surprising addition of South America, in a deal to allow the men's showpiece football tournament to start with a 100th birthday party in Uruguay.

FIFA reached an agreement on Wednesday between soccer's continental leaders to accept only one candidate for hosting the 2030 tournament in six countries.

The Spain-Portugal bid grew to add Morocco this year and now also includes long-time bid rivals Argentina, Paraguay and Uruguay.

All six national teams will get automatic entry to the 48-team tournament.

A key lure of the unprecedented three-continent project is being able to open in the Uruguayan capital of Montevideo, where the Centenario Stadium hosted the inaugural 1930 World Cup final.

"The centennial World Cup could not be far from South America, where everything began," said Alejandro Dominguez, the president of South American soccer body CONMEBOL.

"The 2030 World Cup will be played in three continents."

The consensus reached by once-rival soccer continents also let FIFA fast-track the opening of the 2034 edition, an event Australia is also interested in hosting after successfully co-hosting the Women's World Cup this year with New Zealand.

"Football Australia is exploring the possibility of bidding for the 2029 FIFA Club World Cup and/or the FIFA World Cup 2034," Football Australia chief executive James Johnson said in a statement.

"We acknowledge FIFA's communication regarding the FIFA World Cup 2034 and we are encouraged that after the hugely successful FIFA World Cup Qatar 2022 and FIFA Women's World Cup Australia and New Zealand 2023, the football family of Asia and Oceania will once again have the opportunity to showcase their ability to welcome the world and host the best FIFA tournaments."

Saudi Arabia and Australia both are members of the Asian Football Confederation yet the organisation's president, Bahraini royal Sheikh Salman bin Ebrahim Al Khalifa, stated a clear preference on Wednesday.

"The entire Asian football family will stand united in support of the Kingdom of Saudi Arabia's momentous initiative," Sheikh Salman said in an AFC statement, adding it was committed to working for its win. Australia was a losing candidate when Qatar won its hosting vote in 2010.

Either way, the 2034 tournament will almost certainly be played in November and December — like last year's World Cup in Qatar.

Accelerating the choice of a 2034 host to the end of next year will be widely seen as a victory for Saudi Arabia and Crown Prince Mohammed bin Salman, who has built close ties to FIFA president Gianni Infantino.

"We want to celebrate our football culture and share our country with the world," Yasser Al Misehal, the president of the Saudi soccer federation and a member of the FIFA Council, said in a government statement announcing its intention to bid.

The FIFA Council's acceptance of a unified 2030 candidacy still needs formal approval next year at a meeting of the 211 member federations, although that should be just a formality.

The 2034 pick will be at a separate congress, FIFA said.

"In 2030, we will have a unique global footprint, three continents — Africa, Europe and South America — six countries — Argentina, Morocco, Paraguay, Portugal, Spain and Uruguay — welcoming and uniting the world while celebrating together the beautiful game, the centenary and the FIFA World Cup," Infantino said in a statement.