Supporters of Olympic and Paralympic track star Oscar Pistorius await his arrival for his sentencing at the North Gauteng High Court in Pretoria, South Africa, July 6, 2016. [Photo/Agencies]

Some rights groups have said Pistorius, a wealthy white man and international celebrity, has received preferential treatment compared to others without his status or wealth.

He argued that he fired four shots into the door of a toilet cubicle at his luxury Pretoria home in the mistaken belief that an intruder was hiding behind it.

Members of the Women's League of the ruling African National Congress (ANCWL), who have attended the trial in support of the murdered Steenkamp, said the sentence handed down by Masipa was not sufficient.

"First five years, now six years? She is an embarrassment to the justice system," ANCWL spokeswoman Jacqueline Mofokeng said of Masipa. "It is an insult to women in this country."

Outside the court, a group of people held up placards backing the athlete. One read: "Give Oscar his freedom back please".

Steenkamp's father Barry, who said during sentencing hearings that Pistorius must pay for his crime, declined to comment on the prospects for an appeal.

"We'll leave that to the state," he told reporters.