The Polish Swimming Federation (PZP) said that six swimmers had to return before the start of the 2020 Olympics as the swimming federation sent too many athletes. The mistake happened due to an administrative error, the federation said.

After returning to Poland on Sunday, they threatened legal action and called for the head of the PZP to resign over the incident. The swimming team sent to Japan 23 numbers.

"I would like to express my great regret, sadness and bitterness at the situation," PZP director Pawel Slominski said in a statement, AFP reported. Slominski also admitted the mistake and said that it had been motivated by a desire to "allow as many athletes and coaches as possible to take part".

One of the six, Alicja Tchorz, wrote a post on Facebook attacking the "incompetence" of the PZP, saying they had "misunderstood the rules".

"Imagine that you sacrifice five years of your life and... your sacrifice results in a total flop," said Tchorz, who had represented the country in the 2012 and 2016 Olympics.

Another of the six, Mateusz Chowaniec, who had to return, said on Instagram: "This is an absurd situation that should never have happened."

After his gross mistake, Poland's culture and sports ministry asked the PZP president "to immediately submit explanations" over the incident.

The 2020 Tokyo Olympics which was delayed by a year due to the COVID-19 pandemic is all set to start on July 23. The athletes and the staff will have to follow strict COVID-19 protocols and also have to undergo tests daily.

To stem the spread of the virus, officials said that they will be no spectators allowed for certain Olympic sports and there shall be no hugs and handshakes, too.

The authorities also stated that the athletes, up on the podium, will be presented the medals on a tray and will have to put on the medals around their neck on their own.