Lawyers for the convicted sex offender Brock Turner have appeared in court in California seeking to appeal his conviction.

Turner, a former Stanford University swimmer, was convicted on three counts in relation to sexually assaulting an unconscious woman in 2015.

The three convictions were for sexual assault of an unconscious person, sexual assault of an intoxicated person, and sexual assault with intent to commit rape.

Superior Court Judge Aaron Persky sentenced him to six months in jail and three years' probation in June 2016, and he was released after serving three months.

The case drew massive global attention, and it was widely considered to be a lenient sentence, provoking a majority of Californians to vote to unseat the judge in a special election last month.

On Tuesday (local time), Turner's lawyer Eric Multhaup argued there is a "lack of sufficient evidence to support three convictions" and an appeal should be granted.

According to CNN, Mr Multhaup's argument rests on when the victim, known as Emily Doe, became unconscious.

"There's no evidence at what point she went from being incapacitated from alcohol to loss of consciousness," he said.

If judges believed Emily Doe was not unconscious during the encounter they could be more likely to grant an appeal, CNN reports.

Attorney Alisha Carlile, representing the state of California, said witnesses had testified in court that they "could tell from 30 feet away" that the victim was unconscious.

The California appeals court will deliberate before making a decision on whether to grant an appeal, likely to be within 90 days.

As it stands, Turner is required to be registered as a sex offender for the rest of his life.

Newshub.