PUNCHING a man who was trying to intervene in a "very public, very drunken and very vocal argument” between he and his wife proved a costly decision for Benjamin Fuller.

Monday's sitting of the Proserpine Magistrate's Court heard Fuller and his wife were holidaying in Brisbane when the incident occurred.

Defence solicitor Raymond Taylor of RJ Taylor Law said "a group of five people” had approached the pair outside their hotel room. "What we have here is a situation where there's an argument between this man and his wife, which is intervened by other people not invited,” he said.

"Both he and his wife objected to those people intervening and upon the approach of three males, the defendant has become involved with them physically.”

"He's punched him in the mouth,” Magistrate Simon Young replied.

"In circumstances where he was threatened,” Mr Taylor rejoined.

Magistrate Young then asked if, in light of this, Fuller was pleading self defence.

The defence reaffirmed the guilty plea, saying Fuller wished the matter dealt with swiftly.

In handing down his judgement, Magistrate Young condemned Fuller's response to the intervention.

"To say that it was a disgraceful public display, I think, sums it up sufficiently,” he said.

Fuller was fined $1500.

While no application for compensation was made and there was no medical evidence to suggest ongoing injury to the man who intervened, Fuller was also ordered to pay $500 compensation.

"And that's more in recognition of what he did and the consequences,” Magistrate Young said.