A partner of a Sydney criminal law firm has admitted there is widespread disagreement in legal circles – let alone the general community – about the issue of sexual consent under NSW law.

“The biggest difficulty is the level of disagreement in legal circles and the community generally about what consent is, let alone how it should be defined legally,” said Andrew Tiedt, a criminal lawyer and partner of Sydney firm Armstrong Legal.

Tiedt said that most sexual assault cases have no eyewitnesses and alcohol is frequently involved. This presents serious evidentiary difficulties for the prosecution to prove their case, and to reach the standard required for a conviction – beyond reasonable doubt.

“More often than not, it is simply one word against another,” said Tiedt. “It is always difficult to prove a case when the entire case rests on the evidence of just one person.”

Tiedt’s comments come after NSW Attorney-General Mark Speakman today announced an impending review of sexual consent laws by the NSW Law Reform Commission, in the wake of the Four Corners program that aired on 7 May featuring the high-profile sexual assault trial of Sydney man Luke Lazarus.

Speakman said the bravery of the victim, Saxon Mullins, who relinquished her legal right to anonymity in order to share her story and highlight gaps in the current law, was “commendable”.

“This young woman’s bravery in coming forward and sharing her story is commendable. The delay and uncertainty in this matter was unacceptable,” Speakman said.

Mullins, who was an 18-year-old virgin prior to her encounter with Lazarus, endured two trials and two appeals, in which Lazarus was found guilty by a jury then later had his conviction quashed by the Court of Criminal Appeal. The appeals court refused the prosecution the chance to run a third trial because it said it would be “oppressive” to put Lazarus through the expense and worry of a third trial.

“We can’t legislate for respect, but we can examine whether the consent provisions in our Crimes Act require simplification and modernisation,” said Speakman. “Within the coming weeks I will recommend to the Governor the appointment of a Commissioner with criminal law expertise to lead this important review.”

Saxon Mullins speaking to ABC’s Four Corners program on 7 May.

Minister for the Prevention of Domestic Violence and Sexual Assault Pru Goward said the review was “vital” to ensure survivors felt confident that the justice system was working effectively to keep them safe.

“The law of consent should protect vulnerable people from sexual assault and put offenders on notice,” said Goward. “Reporting sexual assault and reliving the experience in court takes enormous courage, and I look forward to considering the recommendations of this review.”

Tiedt commented that the key issue in many sexual assault cases, including in the Lazarus trial, was not consent, but whether there was “knowledge of consent”. He said that in NSW, there was no specific requirement for “enthusiastic consent”. An accused cannot be found guilty unless the jury is satisfied (beyond a reasonable doubt) that the accused knew the complainant was not consenting, was reckless as to consent, or had no reasonable grounds for believing he or she was consenting.

“Beyond reasonable doubt is a high bar,” said Tiedt. “It can be especially difficult to prove a case when alcohol is involved.”

Laws on the requirement for knowledge of sexual consent vary around the world and even across Australia. Tasmania has Australia’s strictest consent laws, which assume that a person has not consented if they “do not say or do anything to communicate consent”. In Tasmania, if a terrified victim was to “freeze up” and acquiesce to demands – as Mullins claims she did when Lazarus had sex with her in the alleyway behind a King’s Cross nightclub in 2013 – it would likely not be enough to show consent was given.

Goward told The Sydney Morning Herald on Tuesday that she believed NSW should follow Tasmania’s lead in requiring “enthusiastic consent”.

“You must explicitly ask for permission to have sex. If it’s not an enthusiastic yes, then it’s a no,” said Goward.

However, Tiedt said that changing the criminal law to bridge gaps that may have been exposed by the Lazarus case would be a “devilishly complicated task”.

“The law on consent is complicated. The law on knowledge of consent is complicated. It is difficult to explain to juries and difficult for juries to apply to facts as they find them,” said Tiedt. “Making the law clearer while protecting the safety of the community, the rights of complainants and the rights of the accused is an almost impossible task.”

The Four Corners episode that aired on 7 May was shown five years after the alleged incident of sexual assault, but Mullins told ABC reporter Louise Milligan during the program that she had still not come to terms with what happened.

“I know a part of me died that day,” said Mullins.