The 19-year-old man will face court on Wednesday charged with assaulting the woman, also aged 19.

She was left in tears when a chunk of her long, dark hair was snipped off as the route 339 bus travelled through Moore Park on April 13.

A witness told Fairfax Media at the time that a "creepy, freaky" couple had been sitting behind the woman on the bus, which travels from Clovelly into the city, about 9.15am when the woman suddenly became distressed.

"The girl turned around and asked the man 'Did you cut my hair?' " the witness, who did not want to be identified, said.

"She was really distressed. There was a good three or four inches cut off ... "

The passenger said it was a very confusing scene.

The woman was shaking and trying to "hold it together" as she pulled small clumps of hair loose.

The bus driver contacted police, but the alleged offender got off the bus and was last seen getting into a taxi.

Police launched an investigation and examined CCTV footage from the bus.

On Tuesday, officers from the Eastern Beaches Local Area Command saw a man in Avoca Street at Maroubra and tried to stop him, but police allege he ran away.

The officers chased the man and arrested him for outstanding warrants. He was taken to Waverley police station and charged with assault over the bus incident, and the outstanding warrants.

He was refused police bail to appear at Waverley Local Court on Wednesday.