Hayden Anthony Bannister, 25, pleaded guilty to one count of common assault when he appeared in the Launceston Magistrates Court on Tuesday.

Bannister was charged with two counts of common assault, but prosecution tendered no evidence to the first charge and it was dismissed.

The court heard a security guard, Adrian Groves, asked Bannister to leave Showgirls in June last year after he was twice caught using his mobile phone, which the venue prohibits.

As Bannister was being escorted out of the Tamar Street venue, he attempted to punch Mr Groves' face, but it didn't connect because the security guard moved.

During a police interview less than a month after the incident, Bannister said a security guard called his friend a racist slur and he reacted to protect his mate.

Defence lawyer Emily Patch told the court Bannister's behaviour on the night was reactionary and he was intoxicated.

"He regrets his actions," Ms Patch said.

The court heard Bannister had previously drunk alcohol on weekdays and weekends, but three months ago started attending alcoholics anonymous.

Ms Patch said the program helped Bannister reduce his alcohol consumption.

Magistrate Sharon Cure said he had some serious matters in his past.

The court was told the Rocherlea man had not offended since the incident at Showgirls.

Bannister was convicted and fined $500.