Police are investigating the vicious assault of the president of the Ipswich Residents and Ratepayers' Association, Jim Dodrill, who says he and his father were bashed in bushland by up to 20 men on Sunday afternoon.

Mr Dodrill has been treated in hospital for multiple injuries after he and his 73-year-old father were attacked in Collingwood Park, west of Brisbane.

"They threatened to kill me and my father," said Mr Dodrill, who had wanted to document a local resident's concerns about trail bikes in the area.

As area coordinator for Neighbourhood Watch, Mr Dodrill had agreed to meet him.

Jim Dodrill was treated in hospital for multiple injuries. ( Supplied: Jim Dodrill )

He said he was led to a secluded dirt road where he and his father were bashed by men on trail bikes and in four-wheel drives.

"I told them to calm down and back off but they just attacked … and they didn't stop until they got the camera," he said.

"While they [had] me on the ground and stomping on me, one of them was yelling 'kill him, kill him'.

"It was nasty — nothing like I've ever seen before."

Police are deeming the assault to be serious, with no charges laid as of yet. ( ABC News: Melanie Vujkovic )

Councillor 'threatened at same site'

The Criminal Investigation Branch is investigating the alleged assault, during which Mr Dodrill's camera, car, glasses and house keys were stolen.

Mr Dodrill, a karate teacher, said the man who led him and his father to the area ran off.

"I have a fairly good idea how to defend myself and that's why I'm alive now," he said.

He said he had been a vocal opponent of former Ipswich mayor Paul Pisasale, who resigned on June 6 citing ill health.

Jim's father Mitch Dodrill was also injured in the attack. ( Supplied: Jim Dodrill )

Mr Dodrill helped compile a dossier of allegations which independent MP Rob Pyne tabled in State Parliament earlier this month.

Ipswich councillor Kerry Silver told the ABC she visited the private property at Collingwood Park "four or five weeks ago" and was tailgated and cut off by a man who behaved very aggressively.

"I told them they were trespassing," she said.

She said it was a concern for the property owner that four-wheel drivers and trailbike riders were using the site.

"I told the man there were insurance implications for the owners," Cr Silver said.

She said she had requested extra police resources be deployed to deal with the issue.