The family of Oscar Pistorius plan to take legal action against the makers of a film about his life starring South African actor Andreas Damm ©Lifetime

The family of Oscar Pistorius have described a film based on the life of the South African sprinter as a "gross misrepresentation of the truth" and have warned they will take legal action.

The six-time Paralympic champion was sentenced to five years in jail in 2014 for shooting dead his girlfriend Reeva Steenkamp the previous year.

He was released after serving less than a year of his sentence in October 2015 but prosecutors successfully upgraded his conviction to murder, leading to a further six-year punishment.

A film, titled Blade Runner Killer, has been made about Pistorius' life and is due to be released next month.

It has been produced by a United States cable and satellite television company and stars Andreas Damm, a South African actor, and Toni Garrn, a German model.

But Carl Pistorius, Oscar's brother, has said in a statement that his family will take legal action as the film is "not a true reflection" of the events.

"The film was made with blatant disregard of both the Steenkamp and Pistorius families, as well as complete disregard for Reeva and Oscar," read the statement.

"Neither Oscar, the defence or the family were involved in the production of this film in anyway.

"The film is not a true reflection of what happened on the day of this tragedy and the subsequent trial of the matter.

"The film is a gross distortion of the findings of the court.

"It is a gross misrepresentation of the truth.

"The film is rather a representation of what the prosecution tried to portray.

"We will be taking legal action."

Next month South Africa's Supreme Court of Appeal will hear the case of prosecutors against the six-year sentence handed to Pistorius.

The 30-year-old’s sentence was argued to have been "shockingly low", according to prosecutors seeking to increase it.

Prosecutor Gerrie Nel had insisted Pistorius' jail term should have started with 15 years at a minimum.

He claimed Pistorius must have known that someone could be killed when he shot Steenkamp four times through a toilet door.

Nel reiterated those accusations, claiming Pistorius has "never offered a reasonable explanation" for his actions.

Pistorius, however, has always claimed that he suspected an intruder and feared for his life.

Pistorius is eligible for parole in two years' time.