The alleged incident happened on Tuesday in a unit on Kent St in Sydney's CBD.
Police were told of what happened the following day and Sydney City Police Area Command officers opened an investigation.
The 50-year-old was arrested early on Thursday morning at Kent St in Sydney, where he is expected to be charged.
He is expected to appear in court later on Thursday.
O'Keefe was the co-host of Weekend Sunrise from 2005 to 2017 when he announced his resignation as co-host of Weekend Sunrise after 12 years with the show.
He also had roles hosting Deal or No Deal and The Chase Australia.
However, O'Keefe's contract with the Seven Network expired at the end of 2020 and was replaced by Larry Emdur for The Chase Australia.