A rugby player has claimed that he was sexually assaulted by his club captain after a night out in Ashburton.

Ronald Forsyth, 50, from Ashburton, has pleaded not guilty in Timaru District Court to two counts of indecent assault and one of sexual violation by unlawful sexual connection.

A jury was told Forsyth and the player from Allenton Rugby Club had been socialising in Ashburton on June 28 last year, The Timaru Herald reported.

The player, who was taking anti-depressants at the time, told the court he later became ill and was taken home by a friend.

At one stage he woke up and realised someone else was in his bed, touching and kissing him on the neck and cheek.

He said he felt like he was passing in and out of consciousness and at one stage came to and discovered he was being sexually assaulted.

"It was just so terrifying. I didn't have the strength to stop it.

"I thought if a person could do this what else are they capable of," he said.

He became aware a male was with him and ended up striking the man before going into the kitchen, where there were two other people, and vomiting.

Police arrived to find him in the hallway with a duvet around him.

The trial is expected to last two days.