He said tonight (Monday) that he understood the rape allegation is focused on only one player.
In a statement Mr Sorensen said the under-20s players and management team "co-operated fully" with South African police, "after which police advised they were happy for all members of the team to travel home".
"Neither team management nor NZRU have been contacted by the local authorities since then or advised of any further issues or enquiries," Mr Sorensen said.
"If we are contacted we will co-operate and help in any way we can.
"The team has just returned from South Africa and we will discuss the matter further with team management in due course."
The New Age described the investigation as "very low profile and hushed up".
The 22-year-old woman who made the claim reportedly told staff at the front desk of the hotel that she was going to visit her cousin in one of the rooms.
"I can confirm that a woman claimed that she was raped at the hotel. The victim could not tell detectives who raped her because she couldn't remember anything about the incident," police spokesman Col Vish Naidoo told the New Age.
The newspaper quoted a staff member at the hotel saying the woman appeared to have met the rugby players earlier because she knew what rooms they were staying in.
"I think she lives near the hotel. According to some of my colleagues she was apparently drunk. And on Saturday morning she called her parents to fetch her at the hotel after claims that she was raped," the staff member said.
"Her parents insisted on opening a case of rape. We are not certain that she was raped, but there was blood found on a sheet on a bed. The rugby players left the hotel at 12am on Saturday."
Tonight (NZT) Mr Naidoo told APNZ: "Like with any investigation we are always moving forward, but I am not at liberty to disclose any information, especially with this being a rape allegation."
When asked if he could confirm whether the allegation was made against one or multiple players, Mr Naidoo said: "I'm absolutely not able to confirm that at all, we are in the very early stages and won't be able to confirm that until a later stage.
"We cannot say against whom the allegations are being made.
"In rape investigations we do not give a blow-by-blow account. At completion we present the case to the prosecutor who will decide the way forward."
New Zealand's Ministry of Foreign Affairs and Trade (MFAT) tonight said it was aware an issue was raised by local police in Cape Town before the New Zealand under 20 team left.
An MFAT spokesperson said in a statement that the team and team management cooperated fully and assisted local police with their enquiries, after which Cape Town police advised they were happy for all members of the team to travel out of South Africa.
"The NZ High Commission in Pretoria has not negotiated special treatment for the individuals concerned,'' said the spokesperson.
"All New Zealanders overseas are expected to abide by the laws and regulations of the country they are visiting.''