Davis Cup organisers are upset by the announcement of a revamped World Team Cup men's tennis event to be played in Australia from 2020 with $A20 million in prize money plus ranking points.
The International Tennis Federation (ITF), who organise the Davis Cup, say they will press ahead with plans to transform their own competition by staging an 18-team finale from the end of the 2019 season.
They expressed disappointment that the men's governing the ATP had decided to go ahead with its 24-team event to be played at the start of the season.
"We do feel that this was an opportunity missed by the ATP to work together with the ITF in a beneficial and positive way for the whole of tennis," the ITF said in a statement.
Announcing the new World Team Cup earlier on Sunday, ATP president Chris Kermode said in a statement: "This event will enable us to kick off our season with a major team event, with minimal impact on existing players schedules at the start of the year."
The new competition is likely to be a part of the build-up to the Australian Open, which begins in mid-January.
It is not yet clear how that will affect the other tournaments traditionally played in Australia at that time.
Tennis Australia CEO Craig Tiley hailed it as "an exciting new era in men's tennis".
"Upon finalising the agreement with the ATP we look forward to unveiling a stunning new global event in Australia to launch the season," he said
"The world's top players will continue to start their year in Australia in a format that we believe will deeply engage the fans across Australia and throughout the world.
"It will be a great result to be able to stage the ATP World Team Cup within the current calendar while significantly improving player prizemoney."
A smaller World Team Cup was held from 1978 to 2012 in Duesseldorf, Germany. It offered no ranking points and suffered from being held a week before the French Open.
With an already crowded calendar, the ITF, which also runs the women's Fed Cup team event, said: "The continued success of Davis Cup is critical for our sport because the ITF is the only body reinvesting globally into the future development of tennis.
"It is the ITF, alongside our 210 member nations, that develops the pipeline of talent that competes on the men's and women's professional tours and that work relies on the investment created by Davis Cup."
It said ITF member nations would vote in August on the Davis Cup reforms, which addressed changes requested by the ATP player council.
The ATP said details of its new event would be made public "in due course".