Oscar Pistorius's slain girlfriend spoke of the importance of leaving a positive mark in life in a pre-recorded interview released on Saturday, words that two days after her death were laden with poignancy.

"The way that you go out and make your exit is so important, you have either made an impact in a positive way or a negative way," 29-year-old Reeva Steenkamp said in excerpts of a celebrity reality TV show set to air in full later Saturday.

Appearing contemplative and at ease with herself, Steenkamp sits beneath a beach-front palm in the excerpt, dressed in a strappy top and a yellow, black and dotted bikini, with her blonde hair tied back.

The excerpt, filmed in Jamaica for the "Tropika Island of Treasure" programme, also shows Steenkamp swimming with dolphins and smiling broadly as she floats down the jungle-flanked Martha Brae River on a punted bamboo raft.

She also offered some advice to the up to three million people who watch the show every week that, in the wake of her death, sounded like a soliloquy on a life cut short.

"Just maintain integrity and maintain class and just always be true to yourself."

"I'm going to miss you all so much."