A young American woman has described how her abusive former partner choked and beat her before cutting off her little finger during a drug-fuelled altercation at their Perth apartment.

The 36-year-old Perth man is on trial in the District Court charged with four offences including sexual penetration without consent, aggravated assault occasioning bodily harm and unlawful wounding.

The allegations relate to his now 25-year-old former partner whom he met at a drug rehabilitation centre in South East Asia in 2013.

The court was told the accused man, who has denied all charges, lived with his alleged victim for about eight months at the inner-city apartment but their relationship was punctuated by heated arguments and violence.

Prosecutor Alan Dungey told the court the couple’s relationship ended after a row on March 9, 2015 in which the accused choked the victim with a rope and punched her in the face before using a butcher’s knife to sever her right little finger.

Giving evidence yesterday, the woman said they had injected methamphetamine before the altercation at their high-rise apartment.

She said there was a heated argument before the accused became violent, demanding she stay seated on the couch.

“I was trying to get out of the house,” she said. “He went to the bedroom and grabbed a rope to choke me out or strangle me but I was able to get my fingers under it.”

She said when she had tried to run for the door, the man punched her in the face repeatedly and forced her back on to the couch.

“He went and got a chopping board and a kitchen knife from the kitchen and placed the kitchen board under my feet,” she said. “Then he moved it under my right hand.

“I looked over my left shoulder. I felt a warmth and realised it was blood. I looked up at him and my hand and realised my finger was gone.”

The woman said she had tried to wrap her severed finger in a bag of frozen beans but dropped it as she was chased out of the apartment.

Security footage showed the woman running down the street, hiding behind a police car and showing officers her bleeding hand.

The trial continues.