A "sadistic" rapist who attacked and choked two women then refused for years to be treated in jail will not be able to change his appearance without permission for the next five years after an order was made by the Supreme Court.

Luke Daniel Slater, 36, was sentenced to a maximum of 15 years and 6 months behind bars for the "premeditated" rapes in April and November 2001, which a court found were "intended to cause [the victims] to fear for their lives".

In the first attack, Slater - then 19 - followed a 24-year-old woman from a train station at Ingleburn and dragged her into a public toilet block, where he raped and indecently assaulted her. According to facts tendered to the court, he gripped her throat so tightly she became faint and could not speak or breathe, and told her: "I could snap your f---ing neck".

The woman begged for her life. When Slater left, she ran sobbing and distressed to a nearby fire station, where firefighters helped her and attempted to track down a man they had seen sprinting away.

Seven months later, Slater met his second victim - an 18-year-old woman - at a nightclub in Sydney's south. The pair left the club together at 5am and began to have consensual sex nearby, however when the woman pushed Slater away and said "no" he grabbed her throat with both hands and choked her for more than a minute, saying "I want you to die slowly".