PRETORIA (AFP) - Lawyers for Oscar Pistorius will push for the release of the South African "Blade Runner" on Thursday as bail proceedings head into the final stretch after they poked holes in the prosecution's case that he shot dead his model girlfriend.

The Olympic athlete's lawyers on Wednesday showed up shoddy police investigation and undermined witnesses that had supported prosecutors' argument that he intentionally killed Reeva Steenkamp, 29, last Thursday.

But Pistorius now needs to give compelling reasons why he should be let free during his trial, after having spent a week in detention already.

Charged with "premeditated murder", he has to prove exceptional circumstances that his release is in the interest of justice - a high bar for bail.

Under cross-examination investigating officer Hilton Botha agreed that Pistorius' version of the early morning shooting on February 14 fitted the crime scene.

"It sounds consistent," Botha said.

Defence lawyer Barry Roux also cast doubt on key witnesses who suggested a row between the couple before the shooting.

A woman who lives in the same highly secured complex as Pistorius "heard talking that sounded like non-stop fighting from two to three in the morning," hours before she was killed, Prosecutor Gerrie Nel said.

Another witness reported hearing gunshots, screams and then more shots, police said.

"Then he heard a female screaming two-three times, then more gunshots," Botha said.

But Roux disputed these accounts as police said one witness was at least 300 metres from the house and the other had misheard the number of gunshots fired.

Pistorius' family was "satisfied" with the bail hearing, but "finds the contradictions in Botha's testimony extremely concerning," they said in a statement later Wednesday.

Botha was further forced to admit that police hadn't seen a bullet that hit the toilet basin in their investigation. The defence's forensic team discovered the bullet four days later.

He also conceded he did not wear protective clothing when Pistorius' forensic team visited the house, which may have contaminated the scene.

The first double amputee to compete against able-bodied athletes in the Olympics in London last year says he shot Steenkamp by mistake through a locked bathroom door, believing she was a burglar.

She had wounds to her head, elbow and hip.

Medics found her covered in bloodied towels and wearing white shorts and a black vest. She was declared dead on the scene.

Prosecutors later backtracked on the charge that a police search of Pistorius's home found testosterone and needles in a dresser in his bedroom.

"We can't tell what it is," said national prosecuting authority spokesman Medupe Simasiku later said. "We can't confirm or deny it until we get the forensic report." The reports had raised the prospect of illegal doping amid several such international sports scandals.

Lawyers for both sides will wrap up arguments for bail on Thursday.

Prosecutors are expected to say the global celebrity is a flight risk - something he has denied and even Magistrate Desmond Nair questioned.

His family also insisted in a statement "Pistorius does not pose a flight risk, which is evident having regard to his international stature and exposure." A big question is whether the Paralympic champion will use his disability as grounds to argue for his freedom.

He runs on carbon-fibre blades, which inspired his nickname, after being born without the fibulas in both of his legs which were amputated below the knee when he was a baby.

"He's spent years telling the world he is able. What enables him to be able-bodied? Technology. Now if he finds himself without technology, is he able?" asked criminologist Laurie Pieters, who is not involved with the case.

Defence lawyers however refused to comment on their tactic, saying the mystery around their arguments was intentional.

The athlete, who off the track has had a rocky private life with stories of rash behaviour, beautiful women, guns and fast cars, has built up a powerful team of lawyers, medical specialists and public relations experts for his defence.

They have to neutralise his reputation for public outbursts and flirts with danger.

In 2009 he admitted to a newspaper that he slept with a pistol, machine gun, cricket bat and baseball bat for fear of burglars.