A Ferrari driver accused of punching a fellow motorist in 2014 admitted in court yesterday that she had assaulted the man.

But on the second day of her assault trial, Shi Ka Yee, now 72, said that her behaviour was justified as Mr Raphael Chong Yen Ping had abused her with vulgar language.

She also testified that instead of a punch, she had slapped Mr Chong, 39.

When Deputy Public Prosecutor Zhuo Wenzhao asked her if the slap was justified, she replied: "Yes. Two yesses."

Shi said that she was driving her Ferrari to her Pilates class at around 5pm on Feb 25, 2014, when she spotted Mr Chong's stationary BMW along Telok Ayer Street.

As she felt it was blocking her way, she sounded the horn to alert him to move but he did not. She thought he was ignoring her.

Shi was not confident of squeezing past his car due to the width of the Ferrari and stepped out to take pictures on her mobile phone.

She told District Judge Chay Yuen Fatt that she took the pictures as evidence for her insurance in case her car was scratched during an attempt to get past Mr Chong's car. But while she was taking the pictures, he started abusing her with vulgar language, she said.

She added: "I was very stunned, shocked and humiliated... He was not a respectable gentleman. My instinct was to give him a slap (and) I did."

Yesterday, the court heard that in her signed statement to the police in October 2014, she had said: "I was angry at his remarks and I gave him a punch with my right hand while I was still holding on to the phone."

But in court, she disagreed with the word "punch" and maintained that she had slapped Mr Chong instead.

Mr Chong had testified on June 5 that he could not recall using vulgar language on her. He also said Shi had punched him on the right side of his forehead through his open car window. He added that she had rings on her fingers and the blow caused a cut on his forehead. He called the police after she drove off.

His version of events was corroborated by an eyewitness, advertising agency executive director Stephen Choy Ying Whye, who had also testified on June 5.

Shi denied causing Mr Chong's injury and accused Mr Choy of lying.

She has two other charges related to an incident on June 29 last year, when she allegedly stopped her car between the third and fourth lanes of Orchard Road, just after the Claymore Road junction, causing an obstruction.

The verdict for her assault trial is expected to be out on Aug 14. If convicted of assault, she can be jailed up to two years and fined up to $5,000.