The public is being asked for help in finding a man accused of sexually assaulting a woman in north Rockhampton.

An updated description has been released of a man believed to have sexually assaulted a woman in central Queensland.

Police say the woman, 41, was attacked after being chased and tackled to the ground during a night-time walk just after 9pm (AEST) last Friday in grassland adjacent to the Bruce Highway in north Rockhampton.

Officers say the man tried to engage the victim in conversation but when she walked away, he followed her and grabbed her arm.

The woman needed hospital treatment after the attack.

Police released a description of the suspect on Thursday saying the man is described as of Aboriginal or Torres Strait Islander appearance, 175cm tall and stocky with a crew-cut hairstyle and facial stubble.

At the time of the attack he was wearing a black or dark blue T-shirt with a silver or white pattern on the front, dark blue jeans and a belt.