A CAIRNS man is on trial after assaulting his sister at a Rockhampton bus stop by smashing a flagon of port and cutting her elbow, shoulder and ribs.

Kenneth Brian Friday pleaded not guilty to one count of assault causing grievous bodily harm with intent, but guilty to unlawful wounding, in Rockhampton District Court yesterday.

Crown prosecutor Tiffany Lawrence said the jury had to decide if the defendant intended to cause permanent injury when he attacked his sister, Desley, on November 20 about 1pm on Bolsover St at the bus stop outside Kern Arcade.

Desley Friday, 59, told the court her brother normally lived in Cairns but had come down and stayed with her to attend a family member's funeral and decided to stay on for Christmas.

She said on the morning of the assault, Ken and she had walked from her Norman St, Wandal, home to the park across from the Queensland Ambulance Service station where they met up with others and had a 'drink' of moselle.

Desley said they continued walking to the ANZ Bank in Bolsover St where Ken "took all of his money out” before they went to First Choice Liquor and she purchased a flagon of port for $10.

Desley, Ken and their cousin Roxanne spent the morning at the bus stop drinking the port before an argument between Desley and Ken erupted over cigarettes.

Both Desley and Roxanne recalled hearing the flagon being smashed before Ken attacked Desley.

The court was shown CCTV of the trio at the bus stop for about 10-15 minutes prior the attack and then 10 minutes afterwards until police arrived.

Photographs of the injuries after receiving multiple stitches to Desley's left elbow, a small cut to her left shoulder and a cut beneath her left armpit were shown to the jury.

The trial continues on Monday.