"If your right to silence can be taken away from you because of benefit fraud, and you're being investigated in a murder charge ... why do you have it there?" King asked
He suggested one option in the future might be allowing the prosecution to apply to a judge for an order to make it compulsory for an offender to take the stand if it was considered vital enough.
McVicar said the right to silence created an "offender-friendly, criminal-centred legal process".
"I don't think Greg needed to rely on the right to silence in his last case [the Guy trial] - he'd already proven that a doubt existed."
But McVicar said New Zealand should follow the UK's lead in getting rid of the offender's right to silence.
"It appears our legal system is not about truth - if it was the right to silence would not exist,"said McVicar.
Elliott told the audience that King, who represented Clayton Weatherston - the man convicted of murdering his daughter - was the only person who talked to him and his wife, Lesley, through their trial.
"The prosecution ... just ignored us the whole time."