The University of Queensland student elections have erupted into violence, with a candidate hit in the head and then punched several times after he fell to the ground.

The violent daytime attack was caught on video and the offender, who is not believed to be a student nor running in the elections, has been charged by police.

Campbell Ray, a moderate running for Team Rocket, wrote about the incident on his Facebook page.

He said he approached a man who had been cycling around campus all day throwing attack flyers in the air.

When Mr Ray picked one up, it incorrectly said it was authorised by a party which had not given its permission.

"I ran after the guy, reached into the bike basket, and withdrew an armful of flyers and a goon sack," Mr Ray said.

"The guy took a swing at me, I ran away, he chased me and was trying to ram me.

"I dodged behind some bushes, dumped the goon and most of the flyers, he jumped off the bike and kept trying to go after me."

Mr Ray thought the incident was a bit of a joke and did not expect what happened next.

"I got smacked in the head," he said.

"I went down, he punched me in the head a few times more."

Man charged with assault over the incident

UQ Union president Josh Millroy saw the attack unfold and was one of a number of witnesses who restrained the offender until security arrived.

"It burst into an altercation," Mr Millroy said.

"He (Mr Ray) went to run off, then the assailant chased him and king hit him in the back of the head.

"He then proceeded to tackle him and keep hitting him."

Mr Millroy said the man had been handing out flyers which were making derogatory and defamatory remarks about the incumbents.

A 21-year-old Camp Hill man was charged with assault occasioning bodily harm and common assault over the incident, which broke out near the union complex about 2:00pm (AEST) on Monday.

Police will allege he punched a 29-year-old Indooroopilly man and then spat on a 24-year-old Saint Lucia man, who was assisting others to restrain him.

The charged man is due to appear at the Brisbane Magistrates Court on October 28.

Mr Ray said he escaped the attack with mostly superficial wounds.

He lost some skin on his hands and his "muffin-top area".

"My wrist might need looking at and is quite sore, jaw is a bit sore as well," he said.