Associate professor Michael Head, from the University of Western Sydney, said plans by PANSW to push for laws which will allow a jury to draw a negative inference should an accused person choose to remain silent are a move towards arbitrary state and police power and a move away from the notion of innocent until proven guilty.

"I am completely opposed to it," Head told Lawyers Weekly.

"This is about the power of the state over the individual ... It changes the whole balance of power. It makes the powers of the state and the police forces that much greater."

According to Head, any such changes would effectively reverse the onus of proof.

"Essentially, that's what it means. In that way, the accused is obliged to prove their innocence, rather than the other way around," he said.

PANSW announced it would be campaigning for the changes ahead of next March's state election due to the perception that professional criminals are increasingly exploiting the right to silence in NSW, thus making it harder for police to obtain convictions.

Speaking to Lawyers Weekly, PANSW president Scott Weber disputed Head's claims that the onus of proof would be reversed.

"It is patently ridiculous and a misrepresentation of the proposal to suggest that this minor change has any impact whatsoever on the onus of proof," he said.

"The onus still rests with the prosecution to prove its case and the more fundamental principle of innocence until proven guilty is unaltered."

Weber also said changes to the right to silence would make it harder for seasoned criminals to dodge the law, while still protecting innocent people.

"The British Parliament changed the application of the right to silence over 15 years ago to combat the growing misuse of this right, and to deal with the rise of organised crime and terrorism ... The British model still gives people the right to stay silent, but allows for courts to draw an inference of guilt from a person's silence in certain situations," he said in a statement released last week.

For example, Weber said inferences of guilt could be drawn if an accused person unreasonably failed to explain a significant fact in their interview with police, but then later relied on that information as a defence in their trial.

But criminal lawyer and director at Webb & Boland Lawyers Brendan Moylan has questioned the need for such changes.

"If the police are doing their job properly and are investigating each matter thoroughly, then they shouldn't require the availability of an inference of guilt to be drawn from an accused person exercising their right to silence," he told Lawyers Weekly.

Weber responded by saying that the law, as it stands, inhibits the ability of police to properly investigate matters where criminals are able to hide behind the right to silence.

"The purpose of the law should be to protect the community, not to protect criminals. The current laws in fact hamstring police from doing a thorough investigation in circumstances where the accused refuses to reveal evidence they subsequently seek to rely on in court," said Weber.

"This proposed change is not simply about changing the way police do their job - it is about improving the judicial process by providing the court with evidence that has been properly investigated."

The right to silence has existed in NSW for around 120 years, since the Criminal Law and Evidence Amendment Act 1891 came into force, and Moylan said he would be concerned about several factors should the changes be made to a law which has been in place for so long.

"I actually think [the changes] would increase the standard length of hearings and trials, as the defence in a case, when the defendant has remained silent, would want to explain to the court or jury the reasons as to why the defendant remained silent," he explained.

"This would send the trial into a periphery area and, in my opinion, the courts are busy enough without having emphasis placed on periphery matters."

Moylan also said the right for a jury to draw a negative inference from an accused's silence would disadvantage accused persons who harbor a genuine fear and distrust of the police.

"Put simply, I think any deterioration of an accused's right to silence is worrying and should be avoided," he said.

"In my experience, an accused person may ... distrust the police, fearing that the police officers will trick [them] into answering questions and may distort their answers. As such, accused persons are almost always very, very nervous when they give an interview, which then obviously affects both their demeanour during the interview and subsequently their answers - whether they are guilty or not."

Claire Chaffey