The ACT Supreme Court has heard a woman alleging she was raped during a New Year's Eve party looked scared and as if she wanted to escape from the man now accused of the assault.

Steven Howarth, 37, is facing a single charge of sexually assaulting the woman during the party in 2023.

The court has heard the incident happened at an oval where the pair had gone with some children and teenagers to set off a firework.

In evidence played to the court today a teenager said, at the time of the offence, one of the children had called out "they are doing something suss".

The teenager said he saw Mr Howarth hugging the woman from behind.

The boy then said he heard the alleged victim ask another person to stay with them, and say:

The teenager also told the court he had seen Mr Howarth have a lot of drinks at the party, and he was swearing a lot.

In earlier evidence the court heard the pair had exchanged Snapchat details, and that the woman had sent a picture of her chest to him.

Mr Howarth's lawyer Sarah Baker-Goldsmith quizzed the woman about her actions on the night of the alleged rape.

"And you say that does not constitute flirting on your part?" Ms Baker-Goldsmith asked.

"Definitely not," the woman replied.

"You consented to that sexual contact, didn't you?" Ms Baker-Goldsmith asked.

"Definitely not," the woman repeated.

"I know what no means, and I know what stop means."

The trial is continuing in the ACT Supreme Court.