Tennis Australia has announced the creation of the United Cup that is scheduled to run from December 29 to January 8.

Mixed teams from 18 countries are due to compete across the Australian cities of Brisbane, Perth and Sydney during the 11-day tournament.

Prize money is set to total $15 million (£13 million/€15.1 million) with 500 Women's Tennis Association (WTA) and 500 Association of Tennis Professionals (ATP) ranking points also up for grabs.

Each team will comprise of up to four men and four women with ties due to include two women's and two men's singles matches and one mixed doubles matches.

Brisbane, Perth and Sydney will each host two groups of three countries competing in a round-robin format.

The winners of each group will playoff with the victors advancing to the final four in Sydney.

The next-best performing team from the group stage will complete the final-four line-up, with contests due to be played from January 6 to 8.

Australia is guaranteed a spot in the event as the host nation, while other countries will qualify based on their WTA and ATP rankings.

"The United Cup presents a unique opportunity to unite both the men’s and women’s tour in a brand new way that has never been seen before," said Craig Tiley, chief executive of Tennis Australia.

"We have the opportunity here in Australia to leverage tennis' unique position to allow the world's top men and women to compete side by side and represent their country at the highest level.

"We couldn’t be more delighted to see how this event unfolds in January across Brisbane, Perth and Sydney."

ATP chairman Andrea Gaudenzi claimed that the United Cup marked "a major step forward" for the sport.

"Most importantly, it will create incredible new experiences for our fans," said Gaudenzi.

"We’re excited to see the best men’s and women’s players competing together, with ranking points on the line, to launch the season like never before."

WTA chairman and chief executive Steve Simon added: "The United Cup is an important and strategic collaboration between the WTA, the ATP and Tennis Australia that reflects a continued commitment in elevating our sport.

"This exciting singles and mixed doubles team event will bring together emerging stars and established athletes from both tours to compete on the same stage, giving players and fans a unique experience in which the final outcome may be determined with women and men competing together."

The Australian Open - the first grand slam of 2023 - is scheduled to be held from January 16 to 29 in Melbourne.