Police have released CCTV footage showing a woman's struggle to fight off a sexual predator who was pulling her clothes off on the street as people walked past just metres away.

Los Angeles Police Department released the video clip and a sketch of the suspect, who is believed to be Hispanic and aged between 40 and 50, after the incident near Van Nuys Boulevard.

The suspect is believed to have smelled very strongly of alcohol and approached the woman, who has not been named but is in her 30s, as she was leaving her apartment.

After speaking to her in Spanish, a language she does not speak, he refused to let her back inside the building, police said.

He then hauled her to the ground and attacked her as the woman fought back for two to three minutes until he ran off, KTLA reported.

Pedestrians are seen in the video walking past the incident, seemingly failing to intervene or notify the authorities.

The victim “fought like a tiger” and screamed “fire” repeatedly until the man ran away, Captain Lilian Carranza said in a news conference.

"This individual is extremely dangerous and he needs to be taken off the streets,'' Captain Carranza told NBC Los Angeles.

Investigations are underway and the authorities want to speak to anyone who witnessed the crime.

They also raised concerns that no one called police despite having walked past so close to the incident.