Mose Kapeli Esera, 24, had attempted to enter Dubbo's Castlereagh Hotel sometime in the afternoon of October 9 last year, however was refused by security due to his level of intoxication.

According to police, Esera then returned to the hotel a second time at about 12am when he engaged in a conversation with a security guard at the front door.

The incident occurred when Esera walked over to the security guard and punched him in the face, using each hand in a closed fist.

While the security guard didn't have any visible injuries to his face, he fell backwards onto the ground and landed on the brick floor, causing immediate pain and a number of injuries to his back and spine.

Esera continued on and walked down the street before he was stopped by police.

According to court documents, Esera was forthcoming with answers and made full admissions to the assault.

When police asked if he punched someone he said "yeah, he came to me so I punched him".

In court documents, police followed up with the victim and obtained medical records which said he had sustained a number of spinal fractures, and strain to the muscles in his back.

Appearing via video link from New Zealand on Wednesday, Esera pleaded guilty to one count of assault occasioning actual bodily harm and one count of being an excluded person in the vicinity of a licenced premises.

Representing himself, Esera told the court he was in Dubbo to play football, however now resided back in New Zealand.

"It was just a heat of the moment thing, I guess," he said.

Magistrate Theresa Hamilton said Esera had no previous convictions, and said the assault was a "relatively short interaction".

In the circumstances, Magistrate Hamilton fined Esera $550 for the two offences.