JOHANNESBURG (AFP) - During the first week of Oscar Pistorius' murder trial, the judge presiding over the case has come under fire for giving defence lawyers too much leeway and not protecting witnesses.

With the trial broadcast live on television, presiding judge Thokozile Masipa has not escaped the scrutiny of millions watching around the world.

Criticism has centred on Judge Masipa permitting a fierce line of questioning from Mr Barry Roux, Pistorius's defence lawyer, known for his hectoring style of cross-examination.

He has reduced two female witnesses to tears and even read one witness's cellphone number out in court, although he later apologised.

Major South African newspapers have run articles questioning if witnesses are now less likely to come forward, for fear they may face a Roux-like buzz saw.

But his badgering is par for the course, according to some of South Africa's legal fraternity.

"So far I have not noticed any impropriety from the side of the judge," said Ms Mary Nel, a senior criminal law lecturer at the University of Stellenbosch.

"Cross examination is a robust court process, it can get really aggressive."

It is crucial, according to Ms Nel, that the judge does not appear to be taking sides by being too protective of the state witnesses. "The playing field must be level."

"What we have seen so far is the cross examining of the state witnesses by the defence, the same will happen when the state gets to the defence witnesses," she said adding that she expects the same kind of robustness.

Some have criticised Mr Roux for asking witnesses questions seemingly unrelated to testimony or beyond the witness's knowledge.

But according to Ms Nel, sometimes "the pieces of the puzzle will be revealed at a later stage".

Judge Masipa has occasionally stepped in, but some believe she should have intervened more often.

Ms Thea Illsley, a procedural law expert at the University of Pretoria, said that the judge had at times been "decidedly leniently" with Mr Roux.

"The judge is giving Roux leeway to paint a bigger picture of the events, to set a background and context... that is understandable," she said "Some of the questions seem to be beyond the witnesses knowledge."

"The judge has been allowing him to ask questions which may be eventually irrelevant."

For now, most are willing to give Judge Masipa, 66, the benefit of the doubt.

She was appointed a judge in 1998, only the second black woman to be admitted to the bench at the time.

Judge Masipa studied law in her 40s. Before that she was a crime journalist and also a social worker.

In a decade and a half on the bench, she has presided over criminal cases involving rape and murder, and has spoken out strongly about violence against women.

She handed down a 252-year prison sentence to a serial rapist last year, and has been outspoken against the government's rights and responsibilities towards ordinary South Africans.

But none of these cases saw the glare of a trial televised around the world.