The finals of the tournament, previously called the Fed Cup, had been scheduled to take place from April 13 to 18 in Hungary’s capital city Budapest.

The Hungarian National Sports Agency (NSA) and the ITF said extensive work has been undertaken to prepare for the event in April in compliance with national health regulations and with strict COVID-19 protocols in place.

Organisers said several scenarios have been under review, including playing behind closed doors.

Uncertainty and the challenges due to the COVID-19 virus, locally and internationally, have made it unfeasible to host a team competition indoors on the scheduled dates, the ITF said.

"Everyone involved in this competition hoped that we would not be in this position, but unfortunately the Covid-19 situation remains serious and restricting," said ITF President David Haggerty.

"Health and safety comes first.

"Together with the NSA, and in consultation with the Women’s Tennis Association, we are in the process of finalising new dates.

"We continue to work our hardest to deliver a spectacular Finals event in 2021 and, like the players and fans, as well as Billie Jean herself, we are all looking forward to a memorable Billie Jean King Cup Finals later in the year."

The Billie Jean King Cup was formerly known as the Fed Cup, but the tournament was rebranded in September.

The finals had initially been scheduled to take place in Budapest from April 14 to 19 in 2020, before being postponed as a result of the COVID-19 pandemic.

The top 12 national teams will compete over one week to be crowned world champions, with the event set to involve more than 60 athletes, their support teams, officials, and event staff.

France are the defending champions.

The ITF has confirmed the Billie Jean King Cup by BNP Paribas playoff ties, which will be played on a home-and-away basis, will proceed as announced by the host nations on April 16 to 17.