The police are investigating, but had not arrested anyone by Monday evening.
Apparently, the rapist had been waiting for his victim in her bathroom at about midnight.
The woman returned to her room in the Lord Charles Hotel at about 01:00, after she and other members of her group had had a few drinks in the bar.
The man presumably gained access to her ground-floor room through a sliding door, said Superintendent Mary-Anne Williams, acting station commissioner of Somerset West.
When the woman entered the bathroom, the man attacked her and forced her to the bed.
He demanded money and she gave him R3 600 that she had in her purse.
The woman's hands were bound behind her back with the belt of a towelling-cloth bathrobe and one of her shirts was used to gag her so that she couldn't scream.
The man raped her twice on the bed of the hotel room, after which he fell asleep.
He left the premises, presumably on foot, about 03:00 after tying her hands with a telephone cord.
Die Burger heard from a reliable source that at one stage the man had told her that he was not there to rape her, only to rob her.
Returning to Holland
The woman apparently gave permission for the rest of her tour group to be told about her nightmare experience.
The group was staying at the Waterfront on Monday night and the woman was returning to Holland on Thursday.
It is suspected the rapist was not an employee of the Lord Charles Hotel, but someone who had gained access from the street.
Erik Jansen, managing director of the Lord Charles Hotel, said they did not comment on their guests.
A question about security measures in the hotel was also met with a "no comment".