World champions South Africa have withdrawn from the Rugby Championship because of fears over player welfare and disruption amid the Covid-19 pandemic.

New Zealand, Australia and Argentina are left in the tournament, which begins on 31 October in Sydney.

South Africa's top domestic league only resumed on 10 October.

The national side will not play in 2020 - their last match was the World Cup final win over England in November.

South Africa - winners of the Rugby Championship in 2019 - were due to arrive in Australia this weekend before their opening fixture against Argentina on 7 November in Brisbane. All travelling squads are required to quarantine for two weeks on arrival.

On Wednesday, tournament organisers Sanzaar (South Africa, New Zealand, Australia and Argentina Rugby) gave South Africa another 48 hours to agree participation.

"With time essentially having run out, it left us with no option," said Jurie Roux, SA Rugby chief executive.

"This is a hugely disappointing outcome for our supporters and commercial partners but the ongoing impacts of the pandemic in multiple dispensations means we are unable to deliver a Springbok team without seriously compromising player welfare.

"Sanzaar and Rugby Australia have bent over backwards to make the tournament happen and it would have been unfair on them, their partners and state government to delay a decision any longer."

South Africa's withdrawal means the three teams left in the competition will now need to have bye weekends.

The British and Irish Lions are due to tour South Africa next summer, but the hosts could be 20 months without a competitive international by then.