England have questioned the strength of their bio-secure environment in Cape Town after a South African player tested positive for COVID-19, forcing the postponement of the first One-Day International that was scheduled for Newlands on Friday.
The game was moved to Sunday just an hour before it was due to start after the result of the positive test, and the future of the tour will be decided on Saturday when both teams and hotel staff are re-tested again.
Both teams are staying in the same hotel, though they have been kept separate, apart from when they are on the pitch.
"England have expressed a concern and questioned the confidence they have in the bio-secure environment and rightfully so if there is a player who has tested positive having contracted the virus in the last week. We respect that concern," South Africa team doctor Shuaib Manjra said in a video released on Friday.
"Clearly there has been some sort of breach, which we have investigated extensively to determine where this happened. We have spoken to the player, looked at security cameras and other information, and we have not been able to date to identify where that source was. But clearly it is cause for concern."
Manjra denied that any player had left the team hotel without authorisation.
"I can categorically state that no player is able to leave the hotel environment. The security will not allow the player to leave, unless he is doing so in an assigned, official vehicle."
Should Saturday's tests reveal more positive cases, it is likely the tour will be called off and the matches scheduled for Sunday, Monday and Wednesday cancelled.
Managing Director of England Men's Cricket, Ashley Giles, said the decision to retest players is the right one, but did not comment on the potential breach at their hotel.
"On behalf of the England touring party and the ECB, I would like to thank Cricket South Africa for their collaborative approach to postponing today's One-Day International," he said in a media statement.
"Our number one priority is the health and safety of the England team and management group, and the correct decision was made following discussions between the two Boards and respective medical teams."