Kerry Winter disappeared in August 2008 after a quarrel with her former partner, Mark Arnold.
When his trial began in April last year, the prosecution said Arnold clubbed Winter to death with a baseball bat and dumped her body, to which weights had been attached, in the sea. Her body has not been found.
"There's no body or the baseball bat allegedly used in the murder ... Kerry Winter made this up to get her revenge because their relationship had ended," lawyer Yousuf Hammad told the court, reported the English-language daily newspaper, 7Days.
The prosecution claims that Arnold has admitted to the charges but his lawyer told the court on Monday that he confessed under police pressure. Hammad said Winter was upset when her partner of five years dumped her for a new girlfriend. They had argued the day she vanished, but Arnold did not kill her.
"The pair drove into the desert and Arnold tried to calm her down but she kept hitting him and got out of the car, at which point Arnold drove off," said Hammad.
The newspaper reported that Hammad said that, three hours after the supposed murder, a policeman called Kerry on her cellphone and she answered and said that she was fine.
"Winter has used this whole story to punish Arnold," Hammad said, describing the case as "just a woman's revenge".
Arnold told the court: "I was with her but I didn't kill her."
Earlier reports said he told investigators that they had argued and he had hit her on the head with a stick until she bled and fell to the ground.
He has been in custody since August 2008. He received a one-month jail sentence for endangering the life of a house-mate of Winter by swinging a baseball bat at the house-mate when he was alerted to the argument between the two.
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